How and where to mount Class 2 power supply per NFPA 70 - enclosure needed?

randy_m

Member
I'm looking at a residential cove lighting project using some 24V LED strip lights and the following Class 2 power supply:

Looking at NFPA 70 article 450 and 725, it seems like there are no enclosure or ventilation requirements given that the power supply will be a Class 2 power supply and clearly marked as such. Is this true, and can the power supply be mounted onto any surface without any concerns? I am aware that the input side of the power supply will need to be wired to line voltage inside a junction box.

If my understanding of the NEC is correct, why does the following Class 2 power supply have an enclosure box included?

This is my first LED low voltage project - thanks in advance for any help!
 

hbiss

EC, Westchester, New York NEC: 2014
Looking at NFPA 70 article 450 and 725, it seems like there are no enclosure or ventilation requirements given that the power supply will be a Class 2 power supply and clearly marked as such. Is this true, and can the power supply be mounted onto any surface without any concerns? I am aware that the input side of the power supply will need to be wired to line voltage inside a junction box.
Yes.

-Hal
 

randy_m

Member
@hbiss @LarryFine Thank you both for the feedback!

I keep hearing about low voltage (12/24V) LED power supply transformers needing to be in an enclosure box, needing to be accessible for maintenance, not being in a concealed location, needing proper ventilation etc. For example, see the comments section in this video:

Am I correct in my understanding that those rules are applicable to Class 1 systems only, and many folks are simply misinformed about this NOT applying to Class 2?
 

hbiss

EC, Westchester, New York NEC: 2014
First off, that video is one that YouTube needs to take down as dangerous.

Am I correct in my understanding that those rules are applicable to Class 1 systems only, and many folks are simply misinformed about this NOT applying to Class 2?
Class 1 is more restrictive in that both input and output must comply with a Chapter 3 wiring method. So yes, generally an enclosure is needed.

For all drivers and power supplies common sense would dictate proper ventilation and access for service or replacement. I think the problem with Class 2 is that any idiot is encouraged to install it (like by that video) and most idiots have no common sense.

-Hal
 
Here's the brand I usually install: http://gmlighting.net/
What box specifically ? I have preferred Meanwell power supplies as a) I've tested them at work for ripple and b) see previous :)

There's a specific company driver, however, that I want to incorporate- it's 0.1% to 100% dim capable with NO flicker. At least all the traces I've seen and were made for a contract bid. I don't have one in hand though.

But what I need, first of all, is the stupid, bloody code compliant box.
 

hbiss

EC, Westchester, New York NEC: 2014
What box specifically ? I have preferred Meanwell power supplies as a) I've tested them at work for ripple and b) see previous :)

There's a specific company driver, however, that I want to incorporate- it's 0.1% to 100% dim capable with NO flicker. At least all the traces I've seen and were made for a contract bid. I don't have one in hand though.

But what I need, first of all, is the stupid, bloody code compliant box.
What are you talking about? I thought we were answering @randy_m 's question. How about starting your own thread?

-Hal
 
What are you talking about? I thought we were answering @randy_m 's question. How about starting your own thread?

-Hal
I thought you were providing a box that would meet the requirements/specifications of the item he was looking for. From the catalog, with their coverage, there's lots of items, but I thought perhaps you had one in particular in mind- hence my specific question on which box/item.

I was also relating about dimmer control, but I guess that was off topic.

I already do have an open thread on this particular topic so was very excited to see another one that had a new product listed.
 

hbiss

EC, Westchester, New York NEC: 2014
I thought you were providing a box that would meet the requirements/specifications of the item he was looking for.
Don't know why this is a problem. If you want to use a box to house your driver/power supply, Hoffman and others make any number that could be used.

-Hal
 
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