Class 2 wiring?

[Strahan]

A topic of discussion recently came up pertaining to one of our industrial machines regarding class 2 wiring. This machine is located in an industrial setting operating at 240V 3phase. On this machine is of course a 240V 3phase motor 7.5HP along with other I/O devices operating anywhere from 120vac to 12vdc.

The question is: Located within this machine that is an integral part of the machine is a 12V motor. The two leads powering this motor along with terminations are all exposed. One of are new safety managers stated this needed to be placed in conduit and the connections needed sealed. At first he recieved an argument because it is 12V and considered class 2. After looking at article 725 I believe the manager may be right. 725.1 Scope mentions circuits that are not an integral part of the machine which this clearly is.

I'm really lacking in this area and after reading 725 I'm still confused. I realize the classification depends on the supply rating of the power supply, but would any of this matter in this situation? Also this machine does get washed down every night. Thanks for any input!

 

[raider1]

If the Class 2 wiring is an integral part of the equipment then the NEC does not apply and the UL standard that the machine was built to would apply.

If the wiring is field installed then under Article 725 using Class 2 wiring methods there is no requirement that the splices be done in a box.

Chris

 

[nhfire77]

A topic of discussion recently came up pertaining to one of our industrial machines regarding class 2 wiring.

Also this machine does get washed down every night. Thanks for any input!

Its class 3 if its wet, class 2 if not. See UL XOKV Transformers, Class 2, Class 3

 

[pfalcon]

Your company may want to look into adopting NFPA79 "Electrical Standard for Industrial Machinery".

Along with providing good wiring practices as vetted by the fine people at NFPA, it also answers the OSHA question "What standard did you build this machine to?".

Not otherwise required but as good advice -

Conductors and cables shall be run from terminal to terminal without splices or joints.
Exception No. 1: Splices shall be permitted to leads attached to electrical equipment such as motors and solenoids. Such splices shall be insulated with oil-resistant electrical tape or insulation equivalent to that of the conductors and installed in a suitable enclosure.
Exception No. 2: Where it is impracticable to provide terminals in a junction box (e.g., on mobile machines, on machines having long flexible cables), the use of splices or joints shall be permitted.

It is frequently true that when the NFPA79 addresses something that you are not likely to find it in the NEC.

And in other places in the 79 are methods to run the cable without a conduit. Specifically with proper support, proper routing, and grommets to the Jbox.

 

[Strahan]

Your company may want to look into adopting NFPA79 "Electrical Standard for Industrial Machinery".

Along with providing good wiring practices as vetted by the fine people at NFPA, it also answers the OSHA question "What standard did you build this machine to?".

We did not build this machine it was built by an outside vendor. This machine has been installed now for about 10years. We have adopted NFPA 79 and are moving forward with establishing policies to enforce. We have recently hired a new safety manager and he brought this up as being a problem and I'm not real clear on how the different classes apply in this situation. The machine internally was already wired we supplied power to it. Thanks for all the responses. In this case I believe it falls into the UL standards of the machine.

 

[pfalcon]

<snip> We have adopted NFPA 79 and are moving forward with establishing policies to enforce.<snip>In this case I believe it falls into the UL standards of the machine.

I is ecstatic with joy. Go NFPA79!

Then directly to your case:
If the cabling is pre-existing you still fall under the "We can leave this alone if we want to" rule unless your safety requirements say otherwise. Not likely at 12VDC but the safety manager did bring it up. See NFPA79:2007:13 for your answers, not the NEC. The UL requirements are no longer sufficient for your organization.