{"id":3210,"date":"2026-10-20T05:46:31","date_gmt":"2026-10-20T05:46:31","guid":{"rendered":"https:\/\/yocl.com\/?wpr2_import=b874e6300373319917892c206040618073aa0edb637ee67798ef7cd0346c4b82"},"modified":"2026-10-20T05:46:31","modified_gmt":"2026-10-20T05:46:31","slug":"terminal-block-overheating-connection-and-loading-checks","status":"publish","type":"post","link":"https:\/\/yocl.com\/vi\/terminal-block-overheating-connection-and-loading-checks\/","title":{"rendered":"T\u1ea1i sao kh\u1ed1i \u0111\u1ea5u n\u1ed1i c\u1ee7a t\u00f4i b\u1ecb qu\u00e1 nhi\u1ec7t? Nguy\u00ean nh\u00e2n, Ki\u1ec3m tra k\u1ebft n\u1ed1i v\u00e0 Gi\u1edbi h\u1ea1n t\u1ea3i"},"content":{"rendered":"<p><strong>M\u1ed9t c\u1ea7u \u0111\u1ea5u d\u00e2y b\u1ecb qu\u00e1 nhi\u1ec7t c\u00f3 th\u1ec3 do d\u00f2ng \u0111i\u1ec7n qu\u00e1 m\u1ee9c so v\u1edbi c\u00e1c \u0111i\u1ec1u ki\u1ec7n c\u1ee5 th\u1ec3, \u0111i\u1ec7n tr\u1edf ti\u1ebfp x\u00fac t\u0103ng, chu\u1ea9n b\u1ecb d\u00e2y d\u1eabn kh\u00f4ng ph\u00f9 h\u1ee3p, c\u1ea7u n\u1ed1i ho\u1eb7c \u0111\u01b0\u1eddng d\u1eabn ph\u1ee5 ki\u1ec7n b\u1ecb qu\u00e1 t\u1ea3i, nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng cao, kh\u1ea3 n\u0103ng t\u1ea3n nhi\u1ec7t b\u1ecb h\u1ea1n ch\u1ebf ho\u1eb7c linh ki\u1ec7n b\u1ecb h\u01b0 h\u1ecfng.<\/strong> Ng\u1eebng s\u1eed d\u1ee5ng thi\u1ebft b\u1ecb n\u1ebfu \u0111\u1ea7u n\u1ed1i b\u1ecb \u0111\u1ed5i m\u00e0u, ch\u00e1y s\u00e9m, bi\u1ebfn d\u1ea1ng ho\u1eb7c c\u00f3 m\u00f9i kh\u00e9t, v\u00e0 y\u00eau c\u1ea7u ng\u01b0\u1eddi c\u00f3 chuy\u00ean m\u00f4n c\u00e1ch ly v\u00e0 ki\u1ec3m tra tr\u01b0\u1edbc khi xem x\u00e9t. Kh\u00f4ng si\u1ebft ch\u1eb7t, ng\u1eaft k\u1ebft n\u1ed1i ho\u1eb7c ch\u1ea1m v\u00e0o c\u00e1c d\u00e2y d\u1eabn khi c\u1ee5m thi\u1ebft b\u1ecb \u0111ang c\u00f3 \u0111i\u1ec7n.<\/p>\n<p>Vi\u1ec7c t\u0103ng nhi\u1ec7t \u0111\u1ed9 m\u1ed9t ch\u00fat l\u00e0 b\u00ecnh th\u01b0\u1eddng v\u00ec d\u00f2ng \u0111i\u1ec7n \u0111i qua \u0111i\u1ec7n tr\u1edf \u0111i\u1ec7n. Do \u0111\u00f3, c\u00e2u h\u1ecfi h\u1eefu \u00edch kh\u00f4ng ch\u1ec9 \u0111\u01a1n gi\u1ea3n l\u00e0 \u201cn\u00f3 c\u00f3 \u1ea5m kh\u00f4ng?\u201d m\u00e0 l\u00e0 li\u1ec7u nhi\u1ec7t l\u01b0\u1ee3ng c\u00f3 t\u1eadp trung t\u1ea1i ch\u1ed7, t\u0103ng d\u1ea7n theo th\u1eddi gian, li\u00ean quan \u0111\u1ebfn c\u00e1c b\u1ed9 ph\u1eadn b\u1ecb h\u01b0 h\u1ecfng, l\u1eb7p l\u1ea1i sau khi k\u1ebft n\u1ed1i l\u1ea1i hay ch\u1ec9 xu\u1ea5t hi\u1ec7n d\u01b0\u1edbi m\u1ed9t t\u1ea3i tr\u1ecdng c\u1ee5 th\u1ec3. C\u00e1c b\u01b0\u1edbc ki\u1ec3m tra d\u01b0\u1edbi \u0111\u00e2y k\u1ebft n\u1ed1i b\u1eb1ng ch\u1ee9ng \u0111\u00f3 v\u1edbi m\u1ed9t h\u00e0nh \u0111\u1ed9ng ti\u1ebfp theo h\u1ee3p l\u00fd.<\/p>\n<h2>\u0110i\u1ec3m ch\u00ednh c\u1ea7n ghi nh\u1edb<\/h2>\n<ul>\n<li>So s\u00e1nh d\u00f2ng \u0111i\u1ec7n m\u1ea1ch \u0111o \u0111\u01b0\u1ee3c v\u1edbi <strong>d\u00e3y model c\u1ea7u \u0111\u1ea5u ch\u00ednh x\u00e1c<\/strong>, bao g\u1ed3m c\u00e1c \u0111i\u1ec1u ki\u1ec7n l\u1eafp \u0111\u1eb7t v\u00e0 \u0111i\u1ec7n \u0111\u00e3 n\u00eau. Ph\u1ea1m vi d\u00e2y d\u1eabn r\u1ed9ng h\u01a1n kh\u00f4ng t\u1ef1 \u0111\u1ed9ng thi\u1ebft l\u1eadp \u0111\u1ecbnh m\u1ee9c d\u00f2ng \u0111i\u1ec7n cao h\u01a1n.<\/li>\n<li>\u0110i\u1ec7n tr\u1edf ti\u1ebfp x\u00fac t\u0103ng c\u00f3 th\u1ec3 ph\u00e1t sinh t\u1eeb vi\u1ec7c c\u1eafm kh\u00f4ng ho\u00e0n to\u00e0n, chu\u1ea9n b\u1ecb d\u00e2y d\u1eabn sai, s\u1ed1 l\u01b0\u1ee3ng d\u00e2y d\u1eabn kh\u00f4ng ph\u00f9 h\u1ee3p, k\u1eb9p kh\u00f4ng \u0111\u1ee7 ch\u1eb7t ho\u1eb7c k\u1ebft n\u1ed1i b\u1ecb l\u1ecfng.<\/li>\n<li>Thanh n\u1ed1i t\u1eaft, c\u1ea7u n\u1ed1i, thanh c\u00e1i l\u01b0\u1ee3c ho\u1eb7c ph\u1ee5 ki\u1ec7n kh\u00e1c c\u00f3 th\u1ec3 t\u1ea1o th\u00e0nh \u0111\u01b0\u1eddng d\u1eabn d\u00f2ng \u0111i\u1ec7n v\u1edbi c\u00e1c gi\u1edbi h\u1ea1n v\u1ec1 s\u1ea3n ph\u1ea9m v\u00e0 c\u00e1ch b\u1ed1 tr\u00ed ri\u00eang c\u1ee7a ch\u00fang.<\/li>\n<li>Nhi\u1ec7t \u0111\u1ed9 m\u00f4i tr\u01b0\u1eddng, thi\u1ebft b\u1ecb l\u00e2n c\u1eadn, h\u1ec7 th\u1ed1ng th\u00f4ng gi\u00f3 c\u1ee7a v\u1ecf t\u1ee7 v\u00e0 m\u1eadt \u0111\u1ed9 l\u1eafp \u0111\u1eb7t c\u00f3 th\u1ec3 l\u00e0m thay \u0111\u1ed5i nhi\u1ec7t \u0111\u1ed9 c\u1ee7a c\u1ea7u \u0111\u1ea5u m\u00e0 kh\u00f4ng l\u00e0m cho ch\u00ednh t\u1ea3i \u0111\u00f3 b\u1ecb l\u1ed7i.<\/li>\n<li>H\u01b0 h\u1ecfng c\u00f3 th\u1ec3 nh\u00ecn th\u1ea5y, t\u00ecnh tr\u1ea1ng qu\u00e1 nhi\u1ec7t l\u1eb7p \u0111i l\u1eb7p l\u1ea1i ho\u1eb7c t\u00ecnh tr\u1ea1ng l\u1ecfng l\u1ebbo l\u1eb7p \u0111i l\u1eb7p l\u1ea1i \u0111\u00f2i h\u1ecfi ph\u1ea3i thay th\u1ebf ho\u1eb7c b\u00e1o c\u00e1o c\u1ea5p cao h\u01a1n. Vi\u1ec7c si\u1ebft ch\u1eb7t l\u1ea1i m\u1ed9t k\u1ebft n\u1ed1i \u0111ang n\u00f3ng v\u00e0 \u0111\u01b0a n\u00f3 tr\u1edf l\u1ea1i ho\u1ea1t \u0111\u1ed9ng c\u00f3 th\u1ec3 khi\u1ebfn nguy\u00ean nh\u00e2n th\u1ef1c s\u1ef1 kh\u00f4ng \u0111\u01b0\u1ee3c gi\u1ea3i quy\u1ebft.<\/li>\n<\/ul>\n<h2>B\u1eaft \u0111\u1ea7u b\u1eb1ng vi\u1ec7c d\u1eebng an to\u00e0n<\/h2>\n<p>H\u00e3y coi b\u1eb1ng ch\u1ee9ng v\u1ec1 l\u1ed7i \u0111i\u1ec7n \u0111ang ho\u1ea1t \u0111\u1ed9ng l\u00e0 l\u00fd do \u0111\u1ec3 d\u1eebng quy tr\u00ecnh, kh\u00f4ng ph\u1ea3i \u0111\u1ec3 th\u1eed nghi\u1ec7m. C\u01a1 quan Qu\u1ea3n l\u00fd An to\u00e0n v\u00e0 S\u1ee9c kh\u1ecfe V\u01b0\u01a1ng qu\u1ed1c Anh (HSE) gi\u1ea3i th\u00edch r\u1eb1ng thi\u1ebft b\u1ecb \u0111i\u1ec7n c\u00f3 th\u1ec3 xu\u1ed1ng c\u1ea5p trong qu\u00e1 tr\u00ecnh s\u1eed d\u1ee5ng v\u00e0 c\u00e1c v\u1ebft ch\u00e1y ho\u1eb7c v\u1ebft \u1ed1 c\u00f3 th\u1ec3 cho th\u1ea5y t\u00ecnh tr\u1ea1ng qu\u00e1 nhi\u1ec7t; thi\u1ebft b\u1ecb b\u1ecb \u1ea3nh h\u01b0\u1edfng c\u1ea7n \u0111\u01b0\u1ee3c \u0111\u01b0a ra kh\u1ecfi qu\u00e1 tr\u00ecnh s\u1eed d\u1ee5ng v\u00e0 \u0111\u01b0\u1ee3c ki\u1ec3m tra b\u1edfi ng\u01b0\u1eddi c\u00f3 chuy\u00ean m\u00f4n (<a href=\"https:\/\/www.hse.gov.uk\/electricity\/introduction.htm\" target=\"_blank\" rel=\"noopener\">H\u01b0\u1edbng d\u1eabn v\u1ec1 \u0111i\u1ec7n c\u1ee7a HSE<\/a>).<\/p>\n<p>Y\u00eau c\u1ea7u ng\u01b0\u1eddi c\u00f3 chuy\u00ean m\u00f4n tu\u00e2n th\u1ee7 quy tr\u00ecnh \u00e1p d\u1ee5ng t\u1ea1i c\u00f4ng tr\u01b0\u1eddng v\u00e0 thi\u1ebft b\u1ecb \u0111\u1ec3 c\u00e1ch ly m\u1ea1ch \u0111i\u1ec7n v\u00e0 x\u00e1c minh r\u1eb1ng m\u1ea1ch \u0111\u00e3 \u0111\u01b0\u1ee3c ng\u1eaft \u0111i\u1ec7n. L\u01b0u gi\u1eef h\u1ed3 s\u01a1 tr\u01b0\u1edbc khi di chuy\u1ec3n c\u00e1c b\u1ed9 ph\u1eadn: m\u00e3 \u0111\u1ecbnh danh m\u1ea1ch, ki\u1ec3u c\u1ea7u \u0111\u1ea5u, li\u00ean k\u1ebft d\u00e2y d\u1eabn, c\u00e1ch b\u1ed1 tr\u00ed c\u1ea7u n\u1ed1i, tr\u1ea1ng th\u00e1i t\u1ea3i, \u0111\u01b0\u1eddng th\u00f4ng gi\u00f3 v\u00e0 \u1ea3nh ch\u1ee5p b\u1ed1 tr\u00ed ban \u0111\u1ea7u. B\u1ea3o qu\u1ea3n c\u00e1c b\u1ed9 ph\u1eadn b\u1ecb h\u01b0 h\u1ecfng n\u1ebfu c\u00f3 th\u1ec3.<\/p>\n<p>Nh\u1eefng h\u00e0nh \u0111\u1ed9ng n\u00e0y l\u00e0 gi\u1edbi h\u1ea1n \u0111i\u1ec1u tra, kh\u00f4ng ph\u1ea3i l\u00e0 c\u00e1c b\u01b0\u1edbc \u0111\u1ec3 s\u1eeda ch\u1eefa b\u1edfi ng\u01b0\u1eddi kh\u00f4ng c\u00f3 chuy\u00ean m\u00f4n:<\/p>\n<ul>\n<li>Kh\u00f4ng ch\u1ea1m v\u00e0o, si\u1ebft ch\u1eb7t l\u1ea1i, th\u00e1o r\u1eddi ho\u1eb7c ki\u1ec3m tra d\u00e2y d\u1eabn ho\u1eb7c v\u00edt khi \u0111ang c\u00f3 \u0111i\u1ec7n.<\/li>\n<li>Kh\u00f4ng \u0111\u00f3ng l\u1ea1i m\u1ea1ch \u0111i\u1ec7n ch\u1ec9 v\u00ec \u0111\u1ea7u n\u1ed1i \u0111\u00e3 ngu\u1ed9i.<\/li>\n<li>Kh\u00f4ng l\u00e0m s\u1ea1ch c\u00e1c v\u1ebft \u0111\u1ed5i m\u00e0u, v\u1ebft ch\u1ea3y ho\u1eb7c v\u1eadt li\u1ec7u l\u1ecfng l\u1ebbo tr\u01b0\u1edbc khi t\u00ecnh tr\u1ea1ng \u0111\u00f3 \u0111\u01b0\u1ee3c ghi l\u1ea1i.<\/li>\n<li>Kh\u00f4ng thay th\u1ebf m\u1ed9t \u0111\u1ea7u n\u1ed1i b\u1eb1ng m\u1ed9t b\u1ed9 ph\u1eadn c\u00f3 h\u00ecnh th\u1ee9c t\u01b0\u01a1ng t\u1ef1 cho \u0111\u1ebfn khi th\u00f4ng s\u1ed1 k\u1ef9 thu\u1eadt ki\u1ec3u lo\u1ea1i, d\u1eef li\u1ec7u d\u00e2y d\u1eabn, \u0111\u1ed9 t\u01b0\u01a1ng th\u00edch c\u1ee7a ph\u1ee5 ki\u1ec7n v\u00e0 ch\u1ee9c n\u0103ng m\u1ea1ch \u0111i\u1ec7n \u0111\u00e3 \u0111\u01b0\u1ee3c ki\u1ec3m tra.<\/li>\n<\/ul>\n<h2>B\u1ec1 m\u1eb7t n\u00f3ng l\u00e0 b\u1eb1ng ch\u1ee9ng, kh\u00f4ng ph\u1ea3i l\u00e0 ch\u1ea9n \u0111o\u00e1n.<\/h2>\n<p>C\u00e1c kh\u1ed1i \u0111\u1ea7u n\u1ed1i th\u01b0\u1eddng n\u00f3ng h\u01a1n m\u00f4i tr\u01b0\u1eddng xung quanh v\u00ec \u0111\u01b0\u1eddng d\u1eabn d\u00f2ng \u0111i\u1ec7n kh\u00f4ng ph\u1ea3i l\u00e0 v\u1eadt d\u1eabn ho\u00e0n h\u1ea3o. IEC 60947-7-1:2025 \u0111\u1ec1 c\u1eadp \u0111\u1ebfn c\u00e1c kh\u1ed1i \u0111\u1ea7u n\u1ed1i g\u1eafn tr\u00ean gi\u00e1 \u0111\u1ee1 c\u00f4ng nghi\u1ec7p d\u00e0nh cho d\u00e2y d\u1eabn \u0111\u1ed3ng tr\u00f2n v\u00e0 bao g\u1ed3m c\u00e1c y\u00eau c\u1ea7u v\u00e0 th\u1eed nghi\u1ec7m v\u1ec1 \u0111\u1ed9 t\u0103ng nhi\u1ec7t v\u00e0 s\u1ee5t \u00e1p. B\u1ea3n xem tr\u01b0\u1edbc c\u00f4ng khai m\u00f4 t\u1ea3 c\u00e1c \u0111i\u1ec1u ki\u1ec7n v\u1ec1 m\u1eabu th\u1eed, m\u00f4i tr\u01b0\u1eddng xung quanh, l\u1eafp \u0111\u1eb7t v\u00e0 th\u1eed nghi\u1ec7m \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t (<a href=\"https:\/\/webstore.iec.ch\/en\/publication\/72949\" target=\"_blank\" rel=\"noopener\">IEC 60947-7-1:2025<\/a>). Vi\u1ec7c ki\u1ec3m tra b\u00ean trong b\u1ea3ng \u0111i\u1ec1u khi\u1ec3n \u0111ang ho\u1ea1t \u0111\u1ed9ng kh\u00f4ng ph\u1ea3i l\u00e0 thi\u1ebft l\u1eadp th\u1eed nghi\u1ec7m \u0111\u01b0\u1ee3c ki\u1ec3m so\u00e1t \u0111\u00f3.<\/p>\n<p>S\u1ef1 kh\u00e1c bi\u1ec7t n\u00e0y r\u1ea5t quan tr\u1ecdng v\u00ec m\u1ed9t k\u1ebft qu\u1ea3 \u0111o \u0111\u01a1n l\u1ebb c\u00f3 th\u1ec3 b\u1ecb \u1ea3nh h\u01b0\u1edfng b\u1edfi ph\u01b0\u01a1ng ph\u00e1p \u0111o, c\u00e1c ngu\u1ed3n nhi\u1ec7t l\u00e2n c\u1eadn, chu k\u1ef3 t\u1ea3i v\u00e0 \u0111i\u1ec3m tham chi\u1ebfu \u0111\u01b0\u1ee3c ch\u1ecdn. H\u00e3y s\u1eed d\u1ee5ng c\u00e1c thay \u0111\u1ed5i v\u00e0 m\u00f4 h\u00ecnh l\u00e0m b\u1eb1ng ch\u1ee9ng ch\u1ea9n \u0111o\u00e1n, v\u00e0 l\u1ea5y b\u1ea5t k\u1ef3 ng\u01b0\u1ee1ng ch\u1ea5p nh\u1eadn n\u00e0o t\u1eeb h\u01b0\u1edbng d\u1eabn s\u1ea3n ph\u1ea9m ch\u00ednh x\u00e1c, ti\u00eau chu\u1ea9n thi\u1ebft b\u1ecb ho\u1eb7c k\u1ef9 s\u01b0 ch\u1ecbu tr\u00e1ch nhi\u1ec7m.<\/p>\n<table>\n<thead>\n<tr>\n<th>Quan s\u00e1t<\/th>\n<th>Nh\u1eefng g\u00ec b\u1eb1ng ch\u1ee9ng h\u1ed7 tr\u1ee3<\/th>\n<th>Nh\u1eefng g\u00ec kh\u00f4ng th\u1ec3 t\u1ef1 x\u00e1c \u0111\u1ecbnh<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>To\u00e0n b\u1ed9 h\u00e0ng \u0111\u1ec1u \u1ea5m v\u00e0 t\u01b0\u01a1ng t\u1ef1 nhau d\u01b0\u1edbi c\u00f9ng m\u1ed9t t\u1ea3i<\/td>\n<td>S\u1ef1 gia t\u0103ng nhi\u1ec7t \u0111\u1ed9 li\u00ean quan \u0111\u1ebfn d\u00f2ng \u0111i\u1ec7n b\u00ecnh th\u01b0\u1eddng l\u00e0 m\u1ed9t kh\u1ea3 n\u0103ng<\/td>\n<td>R\u1eb1ng d\u00f2ng \u0111i\u1ec7n, k\u1ebft n\u1ed1i ho\u1eb7c vi\u1ec7c l\u1eafp \u0111\u1eb7t l\u00e0 ch\u1ea5p nh\u1eadn \u0111\u01b0\u1ee3c<\/td>\n<\/tr>\n<tr>\n<td>M\u1ed9t \u0111\u1ea7u n\u1ed1i n\u00f3ng h\u01a1n nhi\u1ec1u so v\u1edbi c\u00e1c \u0111\u1ea7u n\u1ed1i gi\u1ed1ng h\u1ec7t nhau mang d\u00f2ng \u0111i\u1ec7n t\u01b0\u01a1ng t\u1ef1<\/td>\n<td>S\u1ef1 kh\u00e1c bi\u1ec7t v\u1ec1 \u0111\u01b0\u1eddng d\u1eabn d\u00f2ng \u0111i\u1ec7n ho\u1eb7c k\u1ebft n\u1ed1i c\u1ee5c b\u1ed9 c\u1ea7n \u0111\u01b0\u1ee3c \u0111i\u1ec1u tra<\/td>\n<td>R\u1eb1ng ch\u1ec9 ri\u00eang m\u1ed9t con v\u00edt l\u1ecfng l\u00e0 nguy\u00ean nh\u00e2n<\/td>\n<\/tr>\n<tr>\n<td>Nhi\u1ec7t \u0111\u1ed9 t\u0103ng d\u1ea7n trong su\u1ed1t chu k\u1ef3 l\u00e0m vi\u1ec7c<\/td>\n<td>Vi\u1ec7c gia nhi\u1ec7t theo th\u1eddi gian, t\u00ecnh tr\u1ea1ng ti\u1ebfp x\u00fac thay \u0111\u1ed5i ho\u1eb7c nhu c\u1ea7u m\u1ea1ch \u0111i\u1ec7n thay \u0111\u1ed5i l\u00e0 \u0111i\u1ec1u h\u1ee3p l\u00fd<\/td>\n<td>Gi\u1edbi h\u1ea1n nhi\u1ec7t \u0111\u1ed9 an to\u00e0n ho\u1eb7c th\u1eddi gian h\u1ecfng h\u00f3c<\/td>\n<\/tr>\n<tr>\n<td>Heat follows a bridge or grouped conductors<\/td>\n<td>The aggregated accessory current path is a priority<\/td>\n<td>The exact bridge rating, routing or acceptable arrangement<\/td>\n<\/tr>\n<tr>\n<td>Heat remains after the circuit load is removed or proven absent<\/td>\n<td>Ambient or external heat may be involved, but the evidence is not conclusive<\/td>\n<td>That the terminal is electrically sound<\/td>\n<\/tr>\n<tr>\n<td>Discolouration, blistering, cracks, deformation or arcing marks are present<\/td>\n<td>Material damage or a serious fault must be considered<\/td>\n<td>That cleaning or re-tightening would restore suitability<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Do not use touch as a measuring instrument. Use a qualified measurement method from the site procedure, record the instrument and reference point, and distinguish a spot temperature from temperature rise above the local ambient. A cooler reading after a temporary load reduction does not remove the need to identify why the condition occurred.<\/p>\n<h2>Separate circuit load from connection resistance<\/h2>\n<p>An overheating investigation should begin with two parallel questions: <strong>what current is this circuit actually carrying, and what does the terminal&#8217;s exact model row permit?<\/strong> A load that exceeds the permitted value requires a circuit or product correction. A compliant load can still produce a hotspot if the effective connection resistance is high.<\/p>\n<p>Increasing heat with current is physically plausible because power dissipated in a resistance rises with the square of current. This general relationship does not supply an ampacity or an acceptance temperature. For the product decision, use the current rating from the same catalogue row as the terminal ordered, together with the conductor and installation conditions attached to that product.<\/p>\n<h3>Read the exact model row<\/h3>\n<p>The examples below show why fields must not be mixed across models. They are YOCL catalogue declarations for the named rows, not independent certification results or a statement that every assembled combination is suitable.<\/p>\n<table>\n<thead>\n<tr>\n<th>ki\u1ec3u d\u00e1ng YOCL<\/th>\n<th align=\"right\">Declared rated current<\/th>\n<th align=\"right\">Declared rated voltage<\/th>\n<th>Declared conductor information<\/th>\n<th align=\"right\">Declared strip length<\/th>\n<th>Other printed information<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><a href=\"https:\/\/yocl.com\/vi\/product\/uk-series-screw-din-rail-terminal-blocks\/\">UK-10RD screw terminal<\/a><\/td>\n<td align=\"right\">10 A<\/td>\n<td align=\"right\">800 V<\/td>\n<td>Rigid 0.5\u201316 mm\u00b2; flexible 0.5\u201316 mm\u00b2<\/td>\n<td align=\"right\">11 mm<\/td>\n<td>M4 screw; the product table does not state a tightening torque<\/td>\n<\/tr>\n<tr>\n<td><a href=\"https:\/\/yocl.com\/vi\/product\/sj-terminal-blocks\/\">SJ-2.5 spring terminal<\/a><\/td>\n<td align=\"right\">24 A<\/td>\n<td align=\"right\">800 V<\/td>\n<td>Rated cross-section 2.5 mm\u00b2; rigid 0.2\u20134 mm\u00b2; flexible 0.2\u20132.5 mm\u00b2<\/td>\n<td align=\"right\">10 mm<\/td>\n<td>The row does not establish every prepared-end or multi-conductor combination<\/td>\n<\/tr>\n<tr>\n<td><a href=\"https:\/\/yocl.com\/vi\/product\/pt-series-push-in-din-rail-terminal-blocks\/\">PT2.5 push-in terminal<\/a><\/td>\n<td align=\"right\">24 A<\/td>\n<td align=\"right\">800 V<\/td>\n<td>Rated cross-section 2.5 mm\u00b2<\/td>\n<td align=\"right\">8\u201310 mm<\/td>\n<td>The single rated cross-section is separate from the rated current<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>The table exposes an important trap: <strong>a larger conductor range does not automatically mean a larger current rating.<\/strong> The 0.5\u201316 mm\u00b2 range printed for UK-10RD does not turn its 10 A row into a 16 mm\u00b2 ampacity claim. Likewise, two families cannot be compared by looking only at 10 A or 24 A. Confirm the full model, circuit function and applicable installation data.<\/p>\n<p>Under the published UL 1059 scope, compliance of a terminal block does not by itself assure suitability in an end product; the actual service conditions can require additional evaluation (<a href=\"https:\/\/www.shopulstandards.com\/ProductDetail.aspx?productId=UL1059_6_S_20241211\" target=\"_blank\" rel=\"noopener\">UL 1059 scope<\/a>). Keep the component declaration, enclosure, conductor system and final equipment assessment in separate evidence fields.<\/p>\n<h3>Compare current and duty with the installed circuit<\/h3>\n<p>Record the current or duty evidence only under the approved method. Then check:<\/p>\n<ul>\n<li>Whether the circuit&#8217;s permitted current includes the actual load cycle and simultaneous loads.<\/li>\n<li>Whether more than one conductor or branch contributes current through the same terminal or accessory.<\/li>\n<li>Whether the current reading represents steady duty, a startup condition or only a favourable moment.<\/li>\n<li>Whether an upstream protection setting was changed without revisiting the circuit&#8217;s conductor and terminal selection.<\/li>\n<li>Whether the terminal&#8217;s model, voltage, conductor type and temperature or environmental conditions match those used when it was selected.<\/li>\n<\/ul>\n<p>If the load exceeds the exact permitted conditions, reduce or rearrange the load according to the equipment design, or specify a correctly rated solution. Do not treat cooling the enclosure as permission to retain an electrically unsuitable current path.<\/p>\n<h2>Inspect clamping and conductor preparation after isolation<\/h2>\n<p>A normal current does not prove a sound connection. Loose or broken electrical connections can create arcing and local heating, while overloaded conductors or components can create ignition risk around nearby materials (<a href=\"https:\/\/www.ul.com\/services\/plastic-materials-testing\" target=\"_blank\" rel=\"noopener\">UL Solutions material-testing explanation<\/a>). That is a reason to inspect the completed current path, not a basis for predicting a particular failure from appearance.<\/p>\n<p>For the relevant terminal family, obtain its exact instructions and compare the installed connection with them.<\/p>\n<figure class=\"wp-block-image\">\n<img decoding=\"async\" src=\"https:\/\/yocl.com\/wp-content\/uploads\/2026\/10\/terminal-block-overheating-connection-and-loading-checks-connection-forms.webp\" alt=\"YOCL screw, cage spring and push-in terminal blocks shown for different clamp inspection checks\"><figcaption>Screw, cage-spring and push-in terminals provide different forms of clamp access. The exact model still governs conductor preparation, operation and inspection.<\/figcaption><\/figure>\n<h3>\u0110\u1ea7u cu\u1ed1i k\u1eb9p v\u00edt<\/h3>\n<p>A screw terminal transfers clamping force through the screw and clamp system. Start with the approved tightening method and value for the exact terminal. If either is unavailable, obtain them before returning the assembly to service; do not copy a torque value from another terminal family or another product&#8217;s instruction.<\/p>\n<p>After isolation, the qualified inspector should look for a screw that does not retain the specified clamping condition, a clamp that has shifted, a conductor positioned outside the intended contact area, a stripped or damaged screw, and a conductor that moves although the clamp has been assembled. A screw that requires repeated re-tightening is evidence of a condition to investigate, not proof that routine re-tightening is an appropriate maintenance strategy.<\/p>\n<p>T\u1ef7 l\u1ec7 <a href=\"https:\/\/yocl.com\/vi\/screw-vs-spring-terminal-blocks\/\">screw versus spring terminal comparison<\/a> explains the wider workflow difference between these clamp types.<\/p>\n<h3>Cage-spring and push-in terminals<\/h3>\n<p>Spring terminals do not use a screw torque setting to create the same clamp action, but they still have exact conductor, preparation, insertion and release requirements. Check that the conductor reached the specified insertion depth, that the correct entry was used, that the spring and entry show no visible damage or deformation, and that the conductor is retained under the intended clamp.<\/p>\n<p>Push-in operation can look deceptively simple. Confirm that the exact model accepts the conductor construction and prepared end, and follow the printed strip length. \u201cPush-in\u201d is also used broadly in product literature, so identify whether the entry has a direct-insertion design or another spring operation. The YOCL <a href=\"https:\/\/yocl.com\/vi\/product\/pt-series-push-in-din-rail-terminal-blocks\/\">PT push-in series<\/a> v\u00e0 <a href=\"https:\/\/yocl.com\/vi\/product\/sj-terminal-blocks\/\">SJ spring series<\/a> are examples of products that must be read as distinct exact-model records.<\/p>\n<h3>Conductor preparation and conductor count<\/h3>\n<p>Inspect the prepared end against the model&#8217;s approved preparation. For stranded or fine-stranded wire, a <a href=\"https:\/\/yocl.com\/vi\/what-is-a-wire-ferrule\/\">wire ferrule<\/a> may be required by the product or wiring specification, but its presence does not prove the assembled connection is correct. Check the <a href=\"https:\/\/yocl.com\/vi\/wire-ferrule-size-chart\/\">ferrule dimensions<\/a> and the terminal&#8217;s printed conductor information separately.<\/p>\n<p>Common evidence to record includes:<\/p>\n<ul>\n<li>The conductor material, construction and cross-section that is actually installed.<\/li>\n<li>The finished prepared end, including any ferrule, sleeve or other termination.<\/li>\n<li>The printed strip length and the amount of conductor visible after assembly.<\/li>\n<li>The number of conductors in one clamping point and whether each entered the intended current-carrying area.<\/li>\n<li>Whether strands, insulation or a ferrule collar sit where the product requires the metal conductor.<\/li>\n<li>Whether the same fault recurs only after a cable is moved, a cover is closed or a bridge is fitted.<\/li>\n<\/ul>\n<p>A conductor that fits into the opening is not automatically an accepted combination. The exact model and the completed connection must both be checked.<\/p>\n<h2>Treat a bridge or accessory as another current path<\/h2>\n<p>A terminal row can look like several independent circuits when a jumper or comb busbar connects them. Electrically, the accessory can create one path that carries the aggregated current before it divides into branches. That path needs its own model identification, current data, insulation or cover arrangement and installation orientation.<\/p>\n<figure class=\"wp-block-image\">\n<img decoding=\"async\" src=\"https:\/\/yocl.com\/wp-content\/uploads\/2026\/10\/terminal-block-overheating-connection-and-loading-checks-bridge-current-path.webp\" alt=\"Conceptual terminal row showing feed current dividing through a comb bridge into three branch conductors\"><figcaption>Conceptual current path: check the feed current, the accessory&#8217;s permitted current and the number and arrangement of branches as one system.<\/figcaption><\/figure>\n<p>Use the following checks after isolation:<\/p>\n<ul>\n<li>Identify the exact bridge or jumper and its approved number of poles or connection positions.<\/li>\n<li>Confirm that it is installed on the terminal models intended to receive it.<\/li>\n<li>Compare the shared feed current and branch arrangement with the accessory&#8217;s exact limits.<\/li>\n<li>Check for an interrupted, partly seated or incorrect-position accessory that can concentrate current in fewer paths.<\/li>\n<li>Check whether covers, end stops or insulating parts are present in the specified arrangement.<\/li>\n<li>Preserve the original bridge position and connection sequence before removing it.<\/li>\n<\/ul>\n<p>The YOCL <a href=\"https:\/\/yocl.com\/vi\/what-is-a-comb-busbar\/\">comb busbar guide<\/a> covers the wider role of these accessories, while the <a href=\"https:\/\/yocl.com\/vi\/pin-vs-fork-comb-busbars\/\">pin versus fork comb busbar comparison<\/a> helps identify the contact format. For the bridge issue itself, the decisive evidence is the exact accessory and terminal combination, not the appearance of an intact plastic cover.<\/p>\n<p>If an accessory is missing its rating or installation information, escalate that gap. Do not infer a current limit from the number of visible pins or from the colour of the plastic.<\/p>\n<h2>Check the thermal environment and installation arrangement<\/h2>\n<p>The same terminal and current can heat differently in two enclosures. Look beyond the terminal for conditions that reduce heat removal or add external heat:<\/p>\n<ul>\n<li>The measured ambient temperature and its variation through the working cycle.<\/li>\n<li>Heat-producing equipment immediately beside or below the terminal row.<\/li>\n<li>Enclosed spaces, blocked ventilation routes and heat trapped under covers.<\/li>\n<li>Dense rows, stacked terminal levels or barriers that alter the installation arrangement.<\/li>\n<li>Insufficient conductor and bending space that strains the connection or blocks access.<\/li>\n<li>Solar loading, process heat and external equipment surfaces where relevant.<\/li>\n<\/ul>\n<p>T\u1ef7 l\u1ec7 <a href=\"https:\/\/yocl.com\/vi\/ts35-din-rail-dimensions\/\">TS35 DIN h\u01b0\u1edbng d\u1eabn k\u00edch th\u01b0\u1edbc thanh ray<\/a> separates rail profile dimensions from device fit. Correct rail size alone does not establish that the terminal has adequate space, conductor access or thermal conditions.<\/p>\n<p>If heat reduces after a temporary external source is removed, record what changed and verify the result after the system returns to its approved operating condition. A fan added during fault finding is not evidence that the installed thermal design is adequate.<\/p>\n<h2>Recognise when replacement or escalation is the right decision<\/h2>\n<p>Some evidence changes the decision from \u201cinvestigate the connection\u201d to \u201cdo not reuse the affected assembly without approval.\u201d<\/p>\n<table>\n<thead>\n<tr>\n<th>\u0110i\u1ec1u ki\u1ec7n<\/th>\n<th>Safe decision boundary<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Discolouration, charring, melted polymer, cracks, deformation, broken insulation or arcing marks<\/td>\n<td>Isolate and replace the affected parts under the approved method; investigate the current path and surrounding damage before reuse<\/td>\n<\/tr>\n<tr>\n<td>Repeated overheating after a documented correction<\/td>\n<td>Escalate; the original diagnosis is incomplete or another cause remains<\/td>\n<\/tr>\n<tr>\n<td>Repeated loosening or a clamp that no longer retains its specified condition<\/td>\n<td>Remove the suspect terminal from service and obtain a replacement\/selection assessment<\/td>\n<\/tr>\n<tr>\n<td>Current or accessory loading outside the exact permitted conditions<\/td>\n<td>Correct the circuit or product arrangement before returning to service<\/td>\n<\/tr>\n<tr>\n<td>Missing torque, preparation, bridge-rating or installation information<\/td>\n<td>Keep the circuit out of fault-repair scope until the required evidence is obtained<\/td>\n<\/tr>\n<tr>\n<td>No identified cause after the safe checks<\/td>\n<td>Escalate to the equipment manufacturer or a qualified electrical engineer rather than returning the circuit to service by assumption<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Replace like-for-like only when the original model, circuit function and installation requirements match. A higher current label on a visually similar terminal is not automatically a safe upgrade: its dimensions, conductor system, accessories, spacing and approvals may differ.<\/p>\n<h2>Build a record that another person can reproduce<\/h2>\n<p>A useful fault record makes the evidence comparable after the circuit has been isolated, cleaned or reassembled.<\/p>\n<table>\n<thead>\n<tr>\n<th>Tr\u01b0\u1eddng h\u1ed3 s\u01a1<\/th>\n<th>Example entry<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Equipment and circuit<\/td>\n<td>Panel identifier, load name, terminal row and circuit number<\/td>\n<\/tr>\n<tr>\n<td>Exact terminal and accessory<\/td>\n<td>Manufacturer, series and model as marked; bridge\/jumper and end-stop models<\/td>\n<\/tr>\n<tr>\n<td>Original evidence<\/td>\n<td>Photographs, local hot area, discolouration, odour, load state and observed timing<\/td>\n<\/tr>\n<tr>\n<td>Electrical comparison<\/td>\n<td>Recorded current or duty evidence and the exact model&#8217;s permitted conditions, with measurement method<\/td>\n<\/tr>\n<tr>\n<td>Connection evidence<\/td>\n<td>Conductor type, cross-section, prepared end, strip result, conductor count, clamping method and specified values<\/td>\n<\/tr>\n<tr>\n<td>Thermal environment<\/td>\n<td>Ambient, adjacent heat sources, enclosure arrangement, ventilation and changes during the test<\/td>\n<\/tr>\n<tr>\n<td>Action and result<\/td>\n<td>Part replaced, connection remade or load changed; repeat observation under the approved service condition<\/td>\n<\/tr>\n<tr>\n<td>Escalation<\/td>\n<td>Person or organization responsible and the evidence still missing<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>Keep the record factual. \u201cTerminal was loose\u201d is weaker than \u201cclamp did not retain the conductor under the specified check\u201d or \u201cconductor entered outside the intended clamp area.\u201d The latter descriptions preserve what was observed and avoid claiming a cause prematurely.<\/p>\n<h2>Choose the next action from the evidence<\/h2>\n<p>Use the evidence in this order:<\/p>\n<ol>\n<li><strong>Unsafe presentation:<\/strong> isolate, verify de-energized, preserve evidence and replace damaged components. Do not restore service after cleaning alone.<\/li>\n<li><strong>Load above the exact permitted conditions:<\/strong> correct the circuit demand or product selection before further operation.<\/li>\n<li><strong>Normal electrical system but a local hotspot:<\/strong> inspect clamping, conductor preparation, conductor count and accessory routing using the exact product instruction.<\/li>\n<li><strong>Heat concentrated around a bridge or jumper:<\/strong> verify the shared current path and accessory arrangement as a system.<\/li>\n<li><strong>No local connection defect but a hotter installation than a comparable panel:<\/strong> investigate ambient, enclosure, adjacent sources and mounting arrangement.<\/li>\n<li><strong>No reliable cause or missing essential data:<\/strong> escalate. A terminal that has cooled is not evidence that the fault has been resolved.<\/li>\n<\/ol>\n<p>For a new-build selection based on the findings, the <a href=\"https:\/\/yocl.com\/vi\/how-to-choose-a-din-rail-terminal-block\/\">DIN-rail terminal selection guide<\/a> starts from conductor and circuit requirements. The <a href=\"https:\/\/yocl.com\/vi\/what-is-a-terminal-block\/\">h\u01b0\u1edbng d\u1eabn kh\u1ed1i \u0111\u1ea7u cu\u1ed1i<\/a> explains the broader product roles, and YOCL&#8217;s <a href=\"https:\/\/yocl.com\/vi\/terminal-blocks-manufacturer\/\">DIN-rail terminal range<\/a> provides the family overview.<\/p>\n<p>When requesting technical support, send the completed evidence record, the exact model markings, the original connection arrangement and photographs of the affected area. Do not include a recommended torque, current or replacement model unless it is supported by the exact product documentation for the assembly.<\/p>\n<h2>T\u00e0i li\u1ec7u tham kh\u1ea3o<\/h2>\n<ul>\n<li>Health and Safety Executive, <a href=\"https:\/\/www.hse.gov.uk\/electricity\/introduction.htm\" target=\"_blank\" rel=\"noopener\">Gi\u1edbi thi\u1ec7u v\u1ec1 an to\u00e0n \u0111i\u1ec7n<\/a>, including signs of equipment deterioration and overheating.<\/li>\n<li>International Electrotechnical Commission, <a href=\"https:\/\/webstore.iec.ch\/en\/publication\/72949\" target=\"_blank\" rel=\"noopener\">IEC 60947-7-1:2025 publication record<\/a>, including the public preview and limited scope\/test context used here.<\/li>\n<li>UL Standards &amp; Engagement, <a href=\"https:\/\/www.shopulstandards.com\/ProductDetail.aspx?productId=UL1059_6_S_20241211\" target=\"_blank\" rel=\"noopener\">UL 1059, Terminal Blocks<\/a>, including the public scope statement concerning terminal-block use in end products.<\/li>\n<li>Gi\u1ea3i ph\u00e1p UL, <a href=\"https:\/\/www.ul.com\/services\/plastic-materials-testing\" target=\"_blank\" rel=\"noopener\">Plastic materials testing<\/a>, explaining ignition and arcing risks associated with overloaded or loose electrical connections.<\/li>\n<li>YOCL \u0110I\u1ec6N, <a href=\"https:\/\/yocl.com\/vi\/product\/uk-series-screw-din-rail-terminal-blocks\/\">UK series screw DIN-rail terminal blocks<\/a>, product information for the UK-10RD fields cited.<\/li>\n<li>YOCL \u0110I\u1ec6N, <a href=\"https:\/\/yocl.com\/vi\/product\/sj-terminal-blocks\/\">SJ terminal blocks<\/a>, product information for the SJ-2.5 fields cited.<\/li>\n<li>YOCL \u0110I\u1ec6N, <a href=\"https:\/\/yocl.com\/vi\/product\/pt-series-push-in-din-rail-terminal-blocks\/\">PT series push-in DIN-rail terminal blocks<\/a>, product information for the PT2.5 fields cited.<\/li>\n<\/ul>","protected":false},"excerpt":{"rendered":"<p>An overheating terminal block can involve excessive current for its exact conditions, increased contact resistance, unsuitable conductor preparation, an overloaded bridge or accessory path, high ambient temperature, restricted heat removal or a damaged component. Stop using the equipment if the terminal is discoloured, charred, deformed or smells hot, and have a qualified person isolate and [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":3209,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[164],"tags":[],"class_list":["post-3210","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-terminals-connections"],"_links":{"self":[{"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/posts\/3210","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/comments?post=3210"}],"version-history":[{"count":1,"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/posts\/3210\/revisions"}],"predecessor-version":[{"id":3211,"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/posts\/3210\/revisions\/3211"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/media\/3209"}],"wp:attachment":[{"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/media?parent=3210"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/categories?post=3210"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/yocl.com\/vi\/wp-json\/wp\/v2\/tags?post=3210"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}