Class1 Div2 Group D 24VDc coils/switches

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bob222

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I am building a large rubber mixing machine. The installation location calls for Class1 Div2 Group D classification. The main motors will be wired on site but other wiring for limit switches prox sensors and solenoid valves have to be done off site. I will use Class1 Div1 Group C 24Vdc components. Can I use MC type or other type of cables to wire from the devices to a junction box? or do I have to use rigid conduit and explosion proof seal fittings? Wire lengths could be up to 15'. I read you are only allowed up to 6' lengths for flexible conduit.

Thank you in advance.

Bob

What comes around goes around
 
Type MC cable is acceptable in Division 2. See Section 501.10 (B)(1)(6) for additional information.

Seal applications will depend on the specific device configuration. See 501.15 ? unfortunately, it can be pretty complex. Solenoids probably will not need seals. Some of the other devices may not either. Without details on those devices ? we can?t say.
 
Class1 Div2 Group D 24VDc coils/switches

Robert thanks for the info I wish I found this forum a long time ago.

I will be using AB hermetically sealed limit switches from the factory. For cable protection can I run the MC cable from these devices inside standard galv conduit and fittings to my junction box and or can I run standard wire from these devices inside the galv conduit?

Thanks,

Bob
 
In Division 2, Type MC cables only need to be installed per Art 330 to be NECcompliant. While MC is permitted “n any raceway” [See 330.10(A)(7)], I wouldn’t recommend it.

RMC or IMC with conventional boxes or conduit bodies and most Table 310.13 conductors is also an acceptable wirirng method . See 501.10 (B)(1)(2) and 501.10(B)(4).

Edit Add: cited RMC/IMC Sections
 
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Class1 Div2 Group D 24VDc coils/switches

501-14(1) (b) states "General -pupose enclosures shall be permitted if current-interupting contacts are one of the following (b) Enclosed within a chamber hermetically sealed...

If this is the case and as I understand Div2, all arcing devices should be enclosed/sealed then I should be able to run standard galv conduit and wiring from these devices to my junction boxes without conduit seals and special fittings?

Comments suggestions would be appreciated

Bob

What comes around goes around
 
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