Is wood allowed in a relay box?

[LarryFine]

Re: Is wood allowed in a relay box?

Originally posted by badjeepr:
try using solid wire then just let the conductors hold the equipment in place..

Bad Jeepr! Bad, bad Jeepr!

 

[infinity]

Re: Is wood allowed in a relay box?

The box in question is a metal gray Hoffman box, 6" by 6" by 4". I fitted a piece of plywood in it with 3/4" lath screws inserted from the back. I mounted two Siemans DPDT 30 AMP, 120 VAC relays on it. [3TX7130--ODF13]

If you go back to the link in my first post you'll see that Hoffman actually makes these boxes with the wood in them.

 

[hardworkingstiff]

Re: Is wood allowed in a relay box?

Originally posted by infinity:
If you go back to the link in my first post you'll see that Hoffman actually makes these boxes with the wood in them.

Of course the box is designed for telephone wiring, not 120 volt or higher wiring.

I've done the wood thing in the past, have had it inspected and passed. I really don't see anything dangerous about it, but..... it may not be exactly "by the book". But then again, neither is driving 56 in a 55 limit.

 

[infinity]

Re: Is wood allowed in a relay box?

Of course the box is designed for telephone wiring, not 120 volt or higher wiring.

I would disagree. Although it's called a telephone cabinet it is listed for use with line voltage relays, controls, etc. Take a look at this from the webpage:

Application
Designed as a housing for electrical controls and instruments. Additional applications include use as a wiring box, junction box, pull box, or telephone and communication cable termination.
Construction
? 16 gauge, 14 gauge, or 12 gauge galvanized steel
? Flush or surface mounting
? Continuous hinge
? Wood mounting panel included
? Tumbler lock with key
Finish
? ANSI 61 gray polyester powder paint on front only
Standards
UL/CUL 50 File No. E27567, Type 1
cUL CSA C22.2 No. 94, File No. E27525, Type 1
NEMA/EEMAC Type 1
IEC 60529, IP30

[ October 08, 2005, 05:06 PM: Message edited by: infinity ]

 

[hardworkingstiff]

Re: Is wood allowed in a relay box?

Originally posted by infinity:

Of course the box is designed for telephone wiring, not 120 volt or higher wiring.

I would disagree. Although it's called a telephone cabinet it is listed for use with line voltage relays, controls, etc. Take a look at this from the webpage:

I stand corrected.

Thanks.

 

[dancase]

Re: Is wood allowed in a relay box?

I guess that this discussion comes down to a question of "what one can get away with" versus "what's the right way to do this."

If you are using an open-frame relay or and enclosed flange-mount relay (as opposed to an enclosed, plug-in relay) You can mount it to the metal box just as well as you can mount a piece of plywood. Even a DIN rail mounted relay socket can usually be directly screw-mounted. That, IMHO, would be far more "right" than a wood panel, and if my name were associated with it the plywood wouldn't be there.

One other thing -- a safety issue -- if this is an open-frame relay, mounting it on the plywood makes any metal mounting flanges, frame, etc ungrounded. Unless it has a totally non-conductive frame, this should be failed at inspection. That can be fixed of course, but between cutting the plywood, mounting it in the box, then moun ting the relay, then running a bonding wire to the box, it would be a lot less work to just mount the relay to the box, IMHO.

If the agenda is to see what you can get away with, why not just ask the inspector?

D.

 

[infinity]

Re: Is wood allowed in a relay box?

I guess that this discussion comes down to a question of "what one can get away with" versus "what's the right way to do this."

I don't see how mounting a piece of plywood in a metal enclosure is 'getting away with' something. It's is not a code issue. As with many facets of this business there are many ways to perform the same task. Some are just better than others.