Panelboard has the wrong voltage rating

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ken44

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A contractor installed a 277/480 volt panelboard in place of what used to be a 120/208 volt panelboard. Is this a code violation or does it impose an inherent danger that an extra label to correctly identify wont fix or does the correctly rated panelboard have to be installed.
 
I don't know why it is a danger but you certainly could get call on it based on 110.3(B). I don't see why it would not work the same or as well as a 120/240 panel -- perhaps re-label the voltage.
 
While I would be less worried that he did it that way vs the other way, I would still have a problem with it.

I might let them get a letter from the manufacture and let them tell us whether it's a big deal or not and then of course I would keep that letter in the file.

Got back just in time to edit. It could be a violation of 408.58, "Panelboards shall be durably marked by the manufacturer with the voltage and the current rating and the number of phases for which they are designed...."
 
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This happens quite often when the designer wants a higher AIC rating. Some 277 volt CB's operating at 120 volts will have an AIC rating of 65k. Here's a photo of one such installation.

2010-11-01_10-42-36_132.jpg
 
I see a lot of 240V panels used on 208V services and that seems to be accepted. It's one of the reasons when I see a 240V panel I require that the voltage be verified. I saw someone install a 240V photovoltaic system only to find out it was a 208V service. Costly mistake.
 
I would think if a panel is rated 277/480 then it surely is rated 120/240. The only issue I see is the label which could easily be re labeled.
 
Dennis Alwon said:
I would think if a panel is rated 277/480 then it surely is rated 120/240. The only issue I see is the label which could easily be re labeled.
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I agree with Dennis, a 277/480V panel should be rated for a lower voltage,
No danger, except breakers are more expensive.

I have seen 120/208 or 120/240V panels were install on a 277/480V feeder. I am not sure what the rating of panel was, but surely the CBs in the panel were not 277/480V rated.
 
The rating of the panelboard is for the maximum voltage, lower voltages are allowed. As an aside, I have had manufacturers direct us to use 480 volt rated gear on 120/208 400HZ installations.

Roger
 
cowboyjwc said:
While I would be less worried that he did it that way vs the other way, I would still have a problem with it.

I might let them get a letter from the manufacture and let them tell us whether it's a big deal or not and then of course I would keep that letter in the file.

Got back just in time to edit. It could be a violation of 408.58, "Panelboards shall be durably marked by the manufacturer with the voltage and the current rating and the number of phases for which they are designed...."
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The voltage and current ratings are the maximum ratings.
There is no violation if you do not exceed those ratings.

To call it a violation of 408.58 is wrong. I would just require a Brady label with the voltage of the system on the panel cover.

Would call it a violation if I used a 600v safety switch on 208v?
 
tkb said:
The voltage and current ratings are the maximum ratings.
There is no violation if you do not exceed those ratings.

To call it a violation of 408.58 is wrong. I would just require a Brady label with the voltage of the system on the panel cover.

Would call it a violation if I used a 600v safety switch on 208v?
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Yes you would relabel it as required per 408.58.

If you went into the plant saw a 277/480 volt panel on the wall and said oh good and ran all of your 277 lighting to it, you would be pretty upset if it was labled wrong.

You guys will argue over whether the ground goes up or down and be serious about it, but not care if a panle is not labeled correctly.
 
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cowboyjwc said:
Yes you would relabel it as required per 408.58.

If you went into the plant saw a 277/480 volt panel on the wall and said oh good and ran all of your 277 lighting to it, you would be pretty upset if it was labled wrong.

You guys will argue over whether the ground goes up or down and be serious about it, but not care if a panle is not labeled correctly.
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What would be sad if the electrician couldn't figure out why the lights are dim or the 480 volt motor won't start.
 
Actually .... the cover is usually where you will find a sticker that identifies ALL the distribution systems for which the panel is approved. This marking is required by the UL listing.

True, the label is almost always upside-down and hard to read- as well as mixed with a variety of other labels. Look for a big paragraph of fine print.

Technically, if the system isn't listed, you are not supposed to use the panel for it.

A classic example of this is when an 'ordinary' 3-phase panel is used on a 240/120 delta system. Most panels do not list this as one of the systems for which it may be used. That's why 'skipping' every third space with your 120-v circuits is not an acceptable practice.
 
renosteinke said:
A classic example of this is when an 'ordinary' 3-phase panel is used on a 240/120 delta system. Most panels do not list this as one of the systems for which it may be used. That's why 'skipping' every third space with your 120-v circuits is not an acceptable practice.
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I'm curious what does this have to do with the panel?
 
While my example has nothing to do with the specific question (using a 480v panel on a 208 service), it has everything to do with that little sticker.

If the sticker does not list 208/120Y as an approved service, the panel is not approved for use with it.

In my example, the panels where you have to 'skip' breaker spaces to prevent your having a 208v-1 pole circuit, you will see that the sticker does NOT include '240/120 Delta" as one of the approved systems for that panel. Thus, skipping spaces can indicate a 110 code violation.

I can't speak for others, but I was in the trade for years before I ever really read one of those labels. It's rather amazing the variety of systems that are often listed. I suspect that the OP will, in fact, find that his "480 Volt" panel does make mention of 208 systems in the 'fine print.' If so, he's good to go.
 
renosteinke said:
In my example, the panels where you have to 'skip' breaker spaces to prevent your having a 208v-1 pole circuit, you will see that the sticker does NOT include '240/120 Delta" as one of the approved systems for that panel. Thus, skipping spaces can indicate a 110 code violation.
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Still not getting the skipping part, are you saying that a 3?, 4W delta panelboard won't have a skipped breaker slots on the B phase if there are a number of 120 volt loads?
 
infinity said:
Still not getting the skipping part, are you saying that a 3?, 4W delta panelboard won't have a skipped breaker slots on the B phase if there are a number of 120 volt loads?
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Panels are factory built today with either A,B,C phase bus links or a combination of A,C and A,B,C links installed. So, yes you can request a panel with a low quantity of B phase provisions. This can also be a field modification for the standard AQ - GE panel.

As indicated previously, proper labeling would be required to maintain the UL listing. You may find it interesting, that the interior of an AQ 280/120V and AE 480/277V are identical - The difference is in the labeling on the dead front and the dead front itself. Both the 480V and 240v breakers will bolt on and mount the same on either interior. The dead fronts will not, if the wrong breaker is installed.
 
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