Couple of questions

[fisherelectric]

On a typical 60/75 degree rated breaker, what does the 40 degree rating after HACR mean? Something to do with ambient operating temp when used as OCP for heating air conditioning and refrigeration equipment?
Also, where in the code does it say that BX cable cannot be used as a ground? For example...extending a circuit from an existing BX wired box with romex.
3rd...what is the code compliant way to hook-up the little electronic transformers for "puck lights" like those made by Wac, for instance when installing them through the top of a cabinet where the only access would be pulling the transformer or box back through the hole for the puck?

 

[Dennis Alwon]

Not sure how to answer the 40C question.

Bx (ac cable) can be used as a ground. Some specs may not allow it but it is legal. Mc must have a ground (I believe).

The only way to wire pucks legally, IMO, is if all the wires and connections are exposed and not hidden in walls, false bottoms, etc.

 

[nakulak]

I was once forced to make all the transformers accessible, and have been doing it since for the puck lighting. the pucks, though, are low voltage and I believe the wiring connections are mostly class 2 ? (at least the ones I did were)

 

[brantmacga]

false bottoms

False bottoms are accessible though.

 

[fisherelectric]

Thanks for the replies,
I'm talking about extending ca 1940s BX if that makes a difference. And as to the pucks....do you install the trans/ in a box with both 120v and 24v in same box? Or surface mount the transformer and extend the leads into a box for splicing to 120v. It seems hard to be code compliant with these things...though I never had a problem with them before I think it's only because I haven't had an inspector look hard enough.

 

[480sparky]

On a typical 60/75 degree rated breaker, what does the 40 degree rating after HACR mean?

Heating, Air Conditioning & Refrigeration.

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Abbreviations

 

[Pierre C Belarge]

Not sure how to answer the 40C question.

Bx (ac cable) can be used as a ground. Some specs may not allow it but it is legal. Mc must have a ground (I believe).

The only way to wire pucks legally, IMO, is if all the wires and connections are exposed and not hidden in walls, false bottoms, etc.

Dennis
Do you have a code section to refer to for this restriction(s)?

 

[fisherelectric]

480sparky, I know what HACR means....it's the 40 degrees I was wondering about.

 

[tonyou812]

if you are working in a plenum or other than .... you have to use mc which is bx with a ground . maybe you are thingking of that code? 300.22

 

[Pierre C Belarge]

Thanks for the replies,
I'm talking about extending ca 1940s BX if that makes a difference. And as to the pucks....do you install the trans/ in a box with both 120v and 24v in same box? Or surface mount the transformer and extend the leads into a box for splicing to 120v. It seems hard to be code compliant with these things...though I never had a problem with them before I think it's only because I haven't had an inspector look hard enough.

The older "BX" (that is UL Standard #4), the armor is not suitable as an equipment ground path. Some time in the '50s, the "newer" AC cable was developed. It has an aluminum bonding conductor installed within the metallic sheathing that makes contact with the sheathing, in essence, "shorting" out all of the small coils (the interlocking metallic sheathing) and permitting the sheathing of AC cable to be an effective ground fault current path.
So, be careful when extending those old "BX" circuits as it is most likey unknown how effective the ground fault current path may be - which means the overcurrent device may not open during a ground fault.



Most of the manufacturers that produce these "low voltage" lighting systems (Class 2 systems) also produce a box for the installation of their Class 2 source (what you are calling the transformer). The 120v wiring and the Class 2 wiring do not share compartments and enter the manufactures enclosures differently. Remember there are restrictions to installing line voltage and Class 2 wiring within the same enclosure - 725.55.


There is an old saying "the job is a lot easier with the correct tools". The same could be said for how hard/how easy some installations may be to be code compliant. "With the correct materials, the job is a lot easier".

 

[infinity]

480sparky, I know what HACR means....it's the 40 degrees I was wondering about.

That's the ambient temperature rating of the breaker.

 

[e57]

Dennis
Do you have a code section to refer to for this restriction(s)?

It has to do with the listing of the fixture as "Portable Cabinet Luminaries". And UL has said that no part of the lighting system be installed behind the building finish - only outside the structure/rock. So do the instructions on most - but then again - most are purposely vague about it IMO. Because they make a lot of sales by misrepresenting what the installation should be.

 

[stickboy1375]

Dennis
Do you have a code section to refer to for this restriction(s)?

I would go with 411.4

 

[fisherelectric]

Pierre, Doesn't 725.55(D) allow the two wiring systems inthe same enclosure? I mean, how else would you hook them up?