Dangerous wiring habits.

Tharon · Jul 25, 2007

I had a problem earlier today with a motor. I opened the panel and started looking at the controls.

I noticed the voltage was not being fed into the top of the fuse block, overload, and contactors. It was being fed into the top, or bottom, which ever was closest.

This doesn't seem safe to me, especially with the fuse block, since when you pull the top of the fuses, the fuses can be exposed while the bottom are still connected to the voltage. I can just see a maintenance employee opening the fuse block while quickly trying to fix it, and touching 480VAC.

Is there anything in the NEC about this type of thing? (Even if there isn't, I personally am rewiring that particular panel to make it safer)

geniusintraining · Jul 25, 2007

Hey...what were you doing in my plant

We have everything wired/programmed every way you can, the Germans (one group) fed from the top, the other group fed from bottom also used black as ground...

always have good batteries in your fluke

abwiz · Jul 26, 2007

As far as I know, there is nothing in the NFPA 70 or 79 about this. Please keep in mind that I don't claim to be an expert in understanding the 'code', so...

I do agree that it goes against standard wriring methods and convention.

Most of the fuse block (holders) for industrial automation are setup so that so that the handle isolates the fuse from the circuit when intalling or removing the fuse. So wiring from the top or bottom would be acceptable from a safety standpoint.

This should really just remind you that you need to have a Lockout-Tagout procedure in place when servicing electrical equipment. And when this makes it impossible to actually do anything (which is usually the case), follow the above advice and make sure you check what is HOT and what is NOT with your Fluke.

But with all that said, I would probably do the same thing as you and rewire the panel so that it follows the somewhat standard convention.

Leon · Jul 26, 2007

Yes

The panel must be a UL listed assembly. (NEC) You can hire UL or some others qualified to inspect the panel and UL list it. All of this for a fee. This is in the code book. (NEC)

This is true (NEC) for ANY custom made panel no matter what size. You can't get by just using UL listed parts. YOU MUST HAVE THE INSPECTION AND STICKER ON THE PANEL. ( Some small 24 volt ones are excluded I think )

Leon

russrmartin · Jul 26, 2007

Leon said:
The panel must be a UL listed assembly. (NEC) You can hire UL or some others qualified to inspect the panel and UL list it. All of this for a fee. This is in the code book. (NEC)

This is true (NEC) for ANY custom made panel no matter what size. You can't get by just using UL listed parts. YOU MUST HAVE THE INSPECTION AND STICKER ON THE PANEL. ( Some small 24 volt ones are excluded I think )

Leon

I disagree. If all hardware is UL listed for an intended use, and is installed correctly and wired according to regulations, then all is well. I've never heard of anyone from UL visiting or hiring someone to inspect panels and post them as UL listed.

Leon · Jul 26, 2007

Russrmartin

You do in Hamilton County, Ohio. Inspection Bureau Inc. 531-381-6080, Gaylord Poe Chief Electrical Inspector. As it is written in the code book. Yes I always thought like you did until they started inforcing this rule about 3 years ago. As I built hundreds of them. When I get time tonight I will look the NEC Article number up and post it on this thread by tomorrow. That will settle this situation. Have to leave now. This is how all the **** from across the pond gets here without UL labels or fake ones and gets sent right back.

Leon

dogleg43 · Jul 26, 2007

Per the NEC, circuit breakers may be fed from the bottom if it is okayed by the manufacturer.

As stated by others in this topic, having the hot wires on the bottom is rather unorthodox and I feel should be avoided.

controlled · Jul 26, 2007

russrmartin said:
I disagree. If all hardware is UL listed for an intended use, and is installed correctly and wired according to regulations, then all is well. I've never heard of anyone from UL visiting or hiring someone to inspect panels and post them as UL listed.

I am note sure about the USA, but I would assume it is similar as Canada. Any equipment being installed has to have the whole assembly inspected and approved by a regulatory agency (UL, CSA, ULC) not just the individual components.

russrmartin · Jul 26, 2007

not sure we're on the same page

When you say panel, I'm not sure we're talking about the same thing. I'm talking about an industrial electrical panel constructed and wired for machine equipment. We've bought several of these, and wired our own as well with nothing of this sort of inspection. The cabinets of course are UL listed for their intended use, and any I.S. wiring etc. is subject to approval from an internal organization, but I've even looked at the code and find nothing. As close as I came was article 110-2 and 3. I'll be interested if you find anything. I'm guessing that you are talking residential or industrial power distribution panels(which also are not inspected here by anyone from UL or UL trained), and that this is a local requirement for you.

In my current role, I am constantly adding and subtracting wiring in panels here, and it has always been up to me to keep everything up to snuff, except for designated circuitry like I.S. wiring that I mentioned before(inspected by a special group). I would assume that if this were required, the company would have asked me to become certified as a UL inspector for this site, which has not happened, nor has it happened in any other facility that I am aware of. 3M is fairly large, and are usually more restrictive on requirements of NFPA70 and other such regulations.

Jimmie_Ohio · Jul 26, 2007

UL stands for Underwriters Laborotories. Underwriters are insurance companies. They do not care if your panel works. The do not care if it is not wired "pretty". They do not care if it is wired with dead shorts. They care that if a listed component fails in a listed enclosure, it is safe from hazard, based on their applicable standard.

I have plenty of experience with this topic since the panel shop I owned had a UL508 file to build control panels.

Now you all can rant about standards and what things should look like and how they should work and what you think you ought to be able to touch when the fuses are half-pulled out of the fuseblock, but don't ASSUME that UL covers this.

What does cover it is NFPA, NEC, and local codes. And if you want appearance or logical arrangement of wiring, that is a company standard or personal pride in building something that looks nice.

Just my thoughts.

controlled · Jul 26, 2007

russrmartin said:
When you say panel, I'm not sure we're talking about the same thing. I'm talking about an industrial electrical panel constructed and wired for machine equipment. We've bought several of these, and wired our own as well with nothing of this sort of inspection. The cabinets of course are UL listed for their intended use, and any I.S. wiring etc. is subject to approval from an internal organization, but I've even looked at the code and find nothing. As close as I came was article 110-2 and 3. I'll be interested if you find anything. I'm guessing that you are talking residential or industrial power distribution panels(which also are not inspected here by anyone from UL or UL trained), and that this is a local requirement for you.

In my current role, I am constantly adding and subtracting wiring in panels here, and it has always been up to me to keep everything up to snuff, except for designated circuitry like I.S. wiring that I mentioned before(inspected by a special group). I would assume that if this were required, the company would have asked me to become certified as a UL inspector for this site, which has not happened, nor has it happened in any other facility that I am aware of. 3M is fairly large, and are usually more restrictive on requirements of NFPA70 and other such regulations.

I was talking about industrial control panels as well as any machinery or equipment.

When new machinery is installed, we have to get a permit and have the electrical installation inspected. The utility inspestor will not approve the installation if the panels or equipment have not been inspected and approved by UL, or CSA.(Complete assembly, not just individual components)

Without the inspectors approval we are not legally allowed to power up the machine or control panel. If we choose to run the equipment and something happens (Blows up, or personal injury) we will not be covered bt our insurance company

Leon · Jul 26, 2007

110.2

Article 110.2 and 110.3 are the ones used here. Yes I am talking about control panels and even custom built equipment. Also notice the FPNs and the AHJ note. I think the best description (what is followed by my inspection agency)is in the UL White Book. It refers to all wiring to be inspected and listed as an assembly. Yes they do get by with panels and breakers and leave this up to the AHJ but they have a UL sticker and define what can be used in the panel board.

Two independent companies here that do the inspections is AAA Inspection and High Voltage Maintence Company and of course UL, and yes they all put a label on the equipment or panel that defines it as a UL LISTED ASSEMBLY.

If that sticker is not on the panel you will not get an approval from the AHJ in Hamilton County or Cincinnati Ohio like we did years ago. We could argue this for years but it would not do me any good if an AHJ in a different city or state approves it and mine doesn't.

Leon

russrmartin · Jul 26, 2007

I think I see the difference here

Leon said:
Article 110.2 and 110.3 are the ones used here. Yes I am talking about control panels and even custom built equipment. Also notice the FPNs and the AHJ note. I think the best description (what is followed by my inspection agency)is in the UL White Book. It refers to all wiring to be inspected and listed as an assembly. Yes they do get by with panels and breakers and leave this up to the AHJ but they have a UL sticker and define what can be used in the panel board.

Two independent companies here that do the inspections is AAA Inspection and High Voltage Maintence Company and of course UL, and yes they all put a label on the equipment or panel that defines it as a UL LISTED ASSEMBLY.

If that sticker is not on the panel you will not get an approval from the AHJ in Hamilton County or Cincinnati Ohio like we did years ago. We could argue this for years but it would not do me any good if an AHJ in a different city or state approves it and mine doesn't.

Leon

I have read, and reread articles 110-2 and 3, not to mention the defininitions of approved, listed, etc. In this I believe I know why we've never had an outside outfit come in, nor sent anyone to approval school if you will. It comes down to the term 'authority having jurisdiction.' I'm going to say that here, someone in my position is considered the authority having jurisdiction, thus, if a panel design meets my standards, it is acceptable without having someone outside from an inspection agency come in. We also don't consider electrical panels as an 'assembly', as they typically are not reproductions of each other. My interest in this post is purely in the context of understanding why you may be required to do this, yet I am not.

P.S. What is AHJ?

Edit: No, I believe the real reason now is article 90-7. Second paragraph pretty much says it all. Thanks though, this was good for me to put my nose in this book again a little bit.

Leon · Jul 26, 2007

Ahj

Authority Having Juristiction.

Leon

allscott · Jul 26, 2007

russrmartin said:
P.S. What is AHJ?

Authority having jurisdiction.

Dangerous wiring habits.

Tharon

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Leon

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controlled

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