產(chǎn)品詳情
1.1 This standard applies to 60 – 250°C single- or multiple-conductor jacketed or unjacketed, integral or nonintegral cables and single or multiple coaxial cables for bephone and other communication circuits such as voice, data, and audio for on-premise customer systems. These cables are may contain one or more optical fibre members. For the purpose of this standard, a coaxial cable or coaxial member conductor is a single conductor with a shield. For the purpose of this standard, a single- or multiple-conductor unjacketed cable is a cross-connect wire.
1.2 This standard applies to communications cables that are intended primarily for installation in accordance with Section 60 of the Canadian Electrical Code Part I, and Article 800 of the National Electrical Code (NEC), ANSI/NFPA 70. They are rated for 300 V applications, but are not so marked.
Note: See Annex a for a complete list of wire types covered by this Standard and the specific electrical codes for which they are intended.
1.3 This standard does not apply to communications cords.
1.4 In Canada, the Type "-CI" circuit integrity markings are not recognized by the Canadian Electrical Code, Part I.
In the US, Type CMH is not recognized in the NEC.
1.5 If a value for measurement is followed by a value in other units in parenthesis, the second value may be only approximate. The first stated value is the requirement.
⊙ CM級(jí)纜線
CM級(jí)纜線是目前最常用的雙絞線阻燃等級(jí)，它的測(cè)試標(biāo)準(zhǔn)為UL 1581。在中國(guó)，常規(guī)的雙絞線幾乎都可以滿足CM級(jí)阻燃測(cè)試。
因此CM級(jí)網(wǎng)線的防火特點(diǎn)如下：
◆ 不會(huì)自燃;
◆ 在火焰中會(huì)冒煙，并可能出現(xiàn)火苗;
◆ 火焰順纜線蔓延的速度很慢;
◆ 當(dāng)外部火源切斷后，纜線上的火苗會(huì)逐漸熄滅。
CM級(jí)纜線只要符合阻燃等級(jí)要求即可，它不考慮煙密度和毒性(在UL 1581中沒(méi)有提及煙密度和毒性)。
CM級(jí)纜線大多是水平雙絞線，在配線子系統(tǒng)中使用。
CM級(jí)纜線的護(hù)套層多為PVC材料，絕緣層則為高密度PE材料。它的優(yōu)點(diǎn)是價(jià)格便宜，而缺點(diǎn)是燃點(diǎn)低，常規(guī)的工作溫度為70℃以下，當(dāng)溫度達(dá)到160℃或更高時(shí)，PVC材料會(huì)散發(fā)出有毒的鹵素和煙霧。如果不幸燒著了它，還會(huì)釋放出大量的熱量。
根據(jù)綜合布線施工規(guī)范，雙絞線應(yīng)該穿金屬管、金屬橋架后敷設(shè)在樓板、天花和墻內(nèi)。這時(shí)，采用普通雙絞線就可以安裝在不需要考慮煙和毒性的任何場(chǎng)合。
⊙ CMR級(jí)纜線
CMR級(jí)纜線屬于美國(guó)UL標(biāo)準(zhǔn)中定義的阻燃纜線之一，主要用于室內(nèi)的垂直主干部分。
當(dāng)纜線垂直放置時(shí)，纜線的方向與火焰的方向一致，而且纜線根數(shù)往往較多，可能引起的火勢(shì)比較大，這時(shí)應(yīng)該采用比普通雙絞線高阻燃等級(jí)的纜線。在美國(guó)的UL標(biāo)準(zhǔn)中，定義CMR級(jí)纜線可以用于垂直干線。
CMR級(jí)纜線的測(cè)試標(biāo)準(zhǔn)為UL 1666，主要用于垂直干線子系統(tǒng)中的纜線。
詳詢陶靜 13913142465
