24 VDC, 2A circuit

[Christmas050873]

I'm wondering if a 24 VDC circuit supplied through a 2A glass fuse requires an EGC? Also what sections of the code support your claims one way or the other?

 

[LarryFine]

Welcome to the forum.

As we often like to do with such questions, first check Art. 250 and tell us what your deduction is.

Just curious, what is the application? Power source, wiring type, load, environment, etc.

 

[Christmas050873]

Welcome to the forum.

As we often like to do with such questions, first check Art. 250 and tell us what your deduction is.

Just curious, what is the application? Power source, wiring type, load, environment, etc.

Equipment Grounding Conductor Required for 24 VDC System?

I have a distributed control system where the system power source originates from 480 VAC powering a 20 amp 24 VDC power supply. The DC common is grounded at the power supply. 24 volt supply circuits are run to various field or machine mounted components. Some of these cables are part of an...

forums.mikeholt.com

Last posting has the following . . .

This subject actually attracted the attention of Mr. Holt himself. In a private discussion, he helped me see that the NEC does not require this 24 Volt system be grounded and therefore would not require an EGC for any part of the circuit.

Unfortunately I don't believe richwaskowitz is alive any longer to ask what specific sections of the code Mike Holt pointed out to him.

 

[LarryFine]

The NEC is considered "permissive" in the sense that something not specifically mandated nor prohibited is optional, meaning that an EGC is not required because it's not required or exceptions allow omitting it.

 

[tortuga]

I used to automatically think all low voltage was class2, and most is, then I saw a communications equipment room that had a 20kVA 48VDC rectifier and the positive was the grounded conductor.

 

[texie]

I used to automatically think all low voltage was class2, and most is, then I saw a communications equipment room that had a 20kVA 48VDC rectifier and the positive was the grounded conductor.

Yes, and this a common misunderstand of the code that just because it is low voltage it is class 2. I see this with LED strip lighting that is only approved for class 2 and the installer thinks he can just use a giant driver that is not class 2 certified do to too much current and all is good.

 

[LarryFine]

I see this with LED strip lighting that is only approved for class 2 and the installer thinks he can just use a giant driver that is not class 2 certified do to too much current and all is good.

What is the current limit for 12v LED drivers to use cl-2 wiring?

 

[petersonra]

What is the current limit for 12v LED drivers to use cl-2 wiring?

The limit is that the power source has to be listed as class 2. And you cannot just put a 2a fuse on a 24 vdc circuit and call it class 2 wiring.