產品詳情
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級纜線
CM級纜線是目前最常用的雙絞線阻燃等級，它的測試標準為UL 1581。在中國，常規(guī)的雙絞線幾乎都可以滿足CM級阻燃測試。
因此CM級網線的防火特點如下：
◆ 不會自燃;
◆ 在火焰中會冒煙，并可能出現(xiàn)火苗;
◆ 火焰順纜線蔓延的速度很慢;
◆ 當外部火源切斷后，纜線上的火苗會逐漸熄滅。
CM級纜線只要符合阻燃等級要求即可，它不考慮煙密度和毒性(在UL 1581中沒有提及煙密度和毒性)。
CM級纜線大多是水平雙絞線，在配線子系統(tǒng)中使用。
CM級纜線的護套層多為PVC材料，絕緣層則為高密度PE材料。它的優(yōu)點是價格便宜，而缺點是燃點低，常規(guī)的工作溫度為70℃以下，當溫度達到160℃或更高時，PVC材料會散發(fā)出有毒的鹵素和煙霧。如果不幸燒著了它，還會釋放出大量的熱量。
根據(jù)綜合布線施工規(guī)范，雙絞線應該穿金屬管、金屬橋架后敷設在樓板、天花和墻內。這時，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合。
⊙ CMR級纜線
CMR級纜線屬于美國UL標準中定義的阻燃纜線之一，主要用于室內的垂直主干部分。
當纜線垂直放置時，纜線的方向與火焰的方向一致，而且纜線根數(shù)往往較多，可能引起的火勢比較大，這時應該采用比普通雙絞線高阻燃等級的纜線。在美國的UL標準中，定義CMR級纜線可以用于垂直干線。
CMR級纜線的測試標準為UL 1666，主要用于垂直干線子系統(tǒng)中的纜線。
詳詢陶靜 13913142465
