Channel Letter Installation: Remote Power Supplies

[tdexxx]

Hello All,

It's been my experience that in led sign installations with remote power supplies, inspectors allow the class 2 power supply wire to run, (in ceiling spaces), between the letters and power supply outside of conduit. I always thought conduit was required for all sign wiring, but inspectors don't seem to object to class 2 wiring being unprotected by conduit. Has the code changed, or do I misunderstand it? Thanks.

[Erik Sine]

Metal conduit or a jacketed cable? In the past metal conduit was required by some because it grounded the letter to the power supply structure, but now I think the new NEC is in effect with no more bonding of class II (oct 10')?

Here in San Diego, we've never had to use conduit for the class II wire, just CL2 rated cable through walls and all.

[imanut]

Hello All,

It's been my experience that in led sign installations with remote power supplies, inspectors allow the class 2 power supply wire to run, (in ceiling spaces), between the letters and power supply outside of conduit. I always thought conduit was required for all sign wiring, but inspectors don't seem to object to class 2 wiring being unprotected by conduit. Has the code changed, or do I misunderstand it? Thanks.

To make a relatively short story. Inspectors are about as unknowledgeable as most sign people about this. You say "inpspectors" - and as such they get to choose what they like and want. Their reasoning for such is up for grabs. UL still requires that metal letters be bonded - whether by conduit or by using the three wire led wire using one for the bond. Some inspectors, out here, like the conduit, flex or otherwise, for "protection" of the wire passing thru the wall. Some have no logic in their decisions. Reality around here, after talking to many local AHJ's - they will go with UL passthrus like the paige ones, and then allow exposed class two wire in the ceiling area. That is legal. They don't allow, around ehre, running class two below the ceiling area. The Paige pass thrus work very well. With the update coming from UL, they are supposedly eliminating the bonding of metal letters.

Furthermore - most inspectors don't know what to look for anyway - so it's entirely possible to illegally wire a sign and get a green tag. If you are a UL shop, you would do well to speak to him about it, praying that he knows a little bit about it, and find out from him. Afterwards - easy to call to the municality to clear things up. And generally speaking, they actually will listen to other "ideas and possibilities" that they didn't know were legal.

gn

[victorysignny]

I agree inspectors know very little about leds. The way I understand NEC If you pass thru an exterior wall you need to protect the wire. We always use MC it makes bonding easy and it looks clean and professional.

[Erik Sine]

Most inspectors just look for a UL section label and then call it a day, hardly any actually open up the letters and PS Box, same for neon.

[tdexxx]

I think the new NEC is in effect with no more bonding of class II (oct 10')?

Interesting. Can anyone confirm that?

[imanut]

I think the new NEC is in effect with no more bonding of class II (oct 10')?

Interesting. Can anyone confirm that?

Actually you need to confirm. I'll explain. UL passes new revisions every three years. However, the municipality is the one that decides IF and WHEN they are going to pass a particular version of UL. That is the deciding factor. I haven't read the current - but I doubt the UL really cares about the protection factor as mentioned by someone - but it might be addressed by the local AHJ.

Check out the new Paige wire and the Paige pass thrus. Much faster, cheaper, etc for LeD wiring than using sealtight, conduit, etc. Certain P/s still need to be mounted in trans box, lockabledisconnect cover if inside and out of site, etc - again, depending onAHJ.

gn

[tdexxx]

I think the new NEC is in effect with no more bonding of class II (oct 10')?

Interesting. Can anyone confirm that?

Actually you need to confirm. I'll explain. UL passes new revisions every three years. However, the municipality is the one that decides IF and WHEN they are going to pass a particular version of UL. That is the deciding factor. I haven't read the current - but I doubt the UL really cares about the protection factor as mentioned by someone - but it might be addressed by the local AHJ.

Check out the new Paige wire and the Paige pass thrus. Much faster, cheaper, etc for LeD wiring than using sealtight, conduit, etc. Certain P/s still need to be mounted in trans box, lockabledisconnect cover if inside and out of site, etc - again, depending onAHJ.

gn

OK. Thanks!

[Brian]

I think the new NEC is in effect with no more bonding of class II (oct 10')?

Interesting. Can anyone confirm that?

Actually you need to confirm. I'll explain. UL passes new revisions every three years. However, the municipality is the one that decides IF and WHEN they are going to pass a particular version of UL. That is the deciding factor. I haven't read the current - but I doubt the UL really cares about the protection factor as mentioned by someone - but it might be addressed by the local AHJ.

Check out the new Paige wire and the Paige pass thrus. Much faster, cheaper, etc for LeD wiring than using sealtight, conduit, etc. Certain P/s still need to be mounted in trans box, lockabledisconnect cover if inside and out of site, etc - again, depending onAHJ.

gn

I looked on the paige site and can't find the pass thrus

[dlaw]

Does any have a picture of properly wired LED letters, I was in the office for a few years while Led were becoming common, everyone I have seen just uses 18-2 doorbell wire or speaker wire passed straight through the wall, I doesn't seem like the right way.

[Erik Sine]

I bought my last CL II wire from Home Depot, very much less expensive than buying from supplier, it's 500 ft for $70 or so. There is CL2 wire that is rated and exists for speaker wire, thermostat & doorbell wiring. Maybe Marko will chime in, he's got a few suggestions from Home Depot and other carriers of CL II wiring.

[imanut]

[i looked on the paige site and can't find the pass thrus

http://www.paigeelectric.com/specs/Paige-Wall-Buster.pdf

[mmartinez]

Keep in mind, per the 2008 NEC, Article 600.7, (B)Bonding, (1) bonding of Metal parts, metal parts and equipment shall be bonded together.....and shall meet the requirements of 250.90. Also, under 600.24, Class 2 Power Sources, (B)Grounding, metal parts of signs and outline lighting systems shall be bonded and grounded in accordance with 600.7.

This is an NEC requirement, not solely a UL requirement. also, a majority of municipalities run one to two code cycles behind the current so if the 2011 code remeoves this requirement, it may still be in force at the local level. Additionally, the AHJ has the right to supercede the requirements of the NEC. From my perspective, the simplest thing to do is provide bonding conductors and include installation instructions for your sub contract installers. Pretty low-cost insurance against a red tag, if you ask me.

[Brian]

Keep in mind, per the 2008 NEC, Article 600.7, (B)Bonding, (1) bonding of Metal parts, metal parts and equipment shall be bonded together.....and shall meet the requirements of 250.90. Also, under 600.24, Class 2 Power Sources, (B)Grounding, metal parts of signs and outline lighting systems shall be bonded and grounded in accordance with 600.7.

This is an NEC requirement, not solely a UL requirement. also, a majority of municipalities run one to two code cycles behind the current so if the 2011 code remeoves this requirement, it may still be in force at the local level. Additionally, the AHJ has the right to supercede the requirements of the NEC. From my perspective, the simplest thing to do is provide bonding conductors and include installation instructions for your sub contract installers. Pretty low-cost insurance against a red tag, if you ask me.

Good advice. Speaking from an installers point of view most manufacturers don't include installation instructions per UL rules.

[neonbndr58]

According to an inspector in Michigan who teaches update classes on the NEC, Bonding is still a requirement for all metal letters. Section 600 requires you to refer to section 250.112. It states that it shal be grounded regardless of voltage and (G) is electric signs and outline lighting in section 600.

The local authority can overide the NEC, BUT only to a higher standard. Not a lower standard.

You have to drill a hole and protect the wires with a passthru for low voltage, so it is just as easy to run flex and be safe.

[Brian]

According to an inspector in Michigan who teaches update classes on the NEC, Bonding is still a requirement for all metal letters. Section 600 requires you to refer to section 250.112. It states that it shal be grounded regardless of voltage and (G) is electric signs and outline lighting in section 600.

The local authority can overide the NEC, BUT only to a higher standard. Not a lower standard.

You have to drill a hole and protect the wires with a passthru for low voltage, so it is just as easy to run flex and be safe.

That depends on the version of the Nec he is teaching. I was under the understanding that jacketed cable did not require to be in conduit?

[imanut]

According to an inspector in Michigan who teaches update classes on the NEC, Bonding is still a requirement for all metal letters. Section 600 requires you to refer to section 250.112. It states that it shal be grounded regardless of voltage and (G) is electric signs and outline lighting in section 600.

The local authority can overide the NEC, BUT only to a higher standard. Not a lower standard.

You have to drill a hole and protect the wires with a passthru for low voltage, so it is just as easy to run flex and be safe.

I'm not sure about the higher standard thing - its not like NEC is a law, it's a standard. I truly believe the AHJ can do whatever..my opinion.

gn

[mmartinez]

According to an inspector in Michigan who teaches update classes on the NEC, Bonding is still a requirement for all metal letters. Section 600 requires you to refer to section 250.112. It states that it shal be grounded regardless of voltage and (G) is electric signs and outline lighting in section 600.

The local authority can overide the NEC, BUT only to a higher standard. Not a lower standard.

You have to drill a hole and protect the wires with a passthru for low voltage, so it is just as easy to run flex and be safe.

I'm not sure about the higher standard thing - its not like NEC is a law, it's a standard. I truly believe the AHJ can do whatever..my opinion.

gn

[mmartinez]

Once a version of a code is adopted, the AHJ can elect to set more stringent standards, (which can be a real PITA if you aren't aware and get tagged). The AHJ has the right to adopt lower standards than the code but will never do that because it then has to assume liability. That's one of the reasons why they delay adopting the most current code until all interpretations have been ferreted out. So, the AHJ can base the normal inspections on the 2008 code but also add anything from the 2011 code as long as it doesn't adopt the 2011 code. It is only required to enforce the adopted code, (plus any of the PITA items). And if your not in good standing with your inspectors......!

[imanut]

Once a version of a code is adopted, the AHJ can elect to set more stringent standards, (which can be a real PITA if you aren't aware and get tagged). The AHJ has the right to adopt lower standards than the code but will never do that because it then has to assume liability. That's one of the reasons why they delay adopting the most current code until all interpretations have been ferreted out. So, the AHJ can base the normal inspections on the 2008 code but also add anything from the 2011 code as long as it doesn't adopt the 2011 code. It is only required to enforce the adopted code, (plus any of the PITA items). And if your not in good standing with your inspectors......!

My old friend, Mike. Glad you jumped on here. Hope you join in more. For those of you that dodn't know Mike - one of the best people that I've ever had the privilege to work with!! And what of the best companies that I ever had the privilege of doing work for....

gn

[Batch]

Gary, are you confusing the NEC's three year code cycle with UL?

The 2011 NEC drops the bonding requirement for LEDs.

Saying that a AHJ can make up more stringent codes scares me. Our code does not allow an inspector to issue a red tag without a specific code section listed as being violated. What? Like the inspector would rather see a #12 bond for secondary rather than #14?

So using the same logic a cop could give you a ticket for doing 32mph in a 35mph zone because he feels 30mph is safer? How about no! LOL

[imanut]

Gary, are you confusing the NEC's three year code cycle with UL?

The 2011 NEC drops the bonding requirement for LEDs.

Saying that a AHJ can make up more stringent codes scares me. Our code does not allow an inspector to issue a red tag without a specific code section listed as being violated. What? Like the inspector would rather see a #12 bond for secondary rather than #14?

So using the same logic a cop could give you a ticket for doing 32mph in a 35mph zone because he feels 30mph is safer? How about no! LOL

I don't think I was confusing the NEC with UL - and I know that I wasn't the one that said a AHJ can make up more stringent codes. What I did say is that an AHJ can - and usually by virtue of the "village" that he is in - can make up their own little rules. Chicago being one of them. They have their own little book, and it's actually bigger than the NEC book. They literally don't care what is in other books.

Your analogy of a cop isn't quite correct. One is a law, the NEC is not a law. Same as UL. They are getting far closer to being in agreement now than they were years ago, and that's a good thing. Yes the NEC code is changing the bonding, and UL is changing its requirements also - but your village has to adopt that particular code book - and I've stated that, I think, several times.

But, as one gets older -- ?

gn

[tdexxx]

In the past metal conduit was required by some because it grounded the letter to the power supply structure

In addition to serving as a means of bonding the letters, isn't conduit also required by the NEC for the protection of conductors from physical damage? (I know that in the Code the word "protection" almost always refers to overcurrent protection, but in this case we're talking physical protection). Does this requirement for physical protection really exist or am I just imagining it? Maybe led power supply secondary conductors aren't required to be protected by conduit because they're class 2?