Code Violation?

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Jeepster

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I am hoping someone may be able to help me with a question. I have found some 3-phase electrical panels wired with a single conductor terminating into A-phase with a jumper between phases A & B, and B & C. I do not think this is a proper installation. I though there was something somewhere in the code or somewhere else that prohibits an electrical device from being used for something other than what it was designed for. I need documentation to support this or the electricians will not correct the issue. Thank you for your help.
 
Wow...

Wow...

ok ... what occupation is "Quality" ... next ... any qualified electrician would know that the installation you descrbed is, well to be blunt, f'd up ... I've seen 2 phases in a 3 phase panel but never just 1 ... where did you see this ... IMO, there wouldn't need to be any documentation to knock this down or tear it out ...
yo Iwire, I checked the 2005 and those articles don't seem to come close to covering this install ... or did I miss something ...
want to hear more ... M
 
mario said:
...I checked the 2005 and those articles don't seem to come close to covering this install ... or did I miss something ...
want to hear more ... M
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110.3(B)Installation and Use.
Listed or labeled equipment shall be installed and used in accordance with any instructions included in the listing or labeling.

I've never seen a 3? panel that didn't indicate all 3 phases were to be used.

110.14 Electrical Connections.
(A) Terminals.
.........
Terminals for more than one conductor and terminals
used to connect aluminum shall be so identified.

Could be that the terminals are listed for only 1 conductor - not a daisy-chain effect.
 
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oooopppss...

oooopppss...

yo Celtic ... thanks ... been a long day just got off work and can't seem to comprehend much (up since 4 am AK time, and 4 beers...) ... still would like to know where this install is at, find it hard to believe anybody would do this ... some more details would be kool ... how/why is there only 1 phase there in the first place ... come on, lets hear "The Rest Of The Story" ... M
 
This application was installed on a US military base in Iraq. Being a QA/QC inspector we are required to inspect everything and ensure that the installations are per the NEC. I came across this and i was thinking that there was probably a UL listing or another standard that prohibited a device from being used other than what it was designed for. These are EXPAT electricians that are performing the work and sometimes it is scary. I appreciate the replys that i received. All of our power is 3-phase and it don't make sense to me the way they did it. One of the first thing that is said when we come across a deficiency is, "show me documentation to say it is wrong". Thanks again guys..
 
Assuming the lugs are rated for more than one conductor, what is actually wrong with doing this? If all the loads are 120-volt and the feeder has proper sizing and overcurrent protection why would it not be safe?
 
I am with hardworkingstiff.

I see no problem with this installation as long as the lugs are rated for multiple conductors and the panel is rated for the line to neutral voltage. But I would suggest contacting the manufacturer. Installation instructions supplied with equipment do/can not cover every conceivable question.
 
jim dungar said:
I am with hardworkingstiff.

I see no problem with this installation as long as the lugs are rated for multiple conductors and the panel is rated for the line to neutral voltage. But I would suggest contacting the manufacturer. Installation instructions supplied with equipment do/can not cover every conceivable question.
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Jim I do not recall seeing a three phase panel that gave instructions on how to use it for single phase, perhaps an I-Line might as they are a strange panel.

If the tag on the panel does not say single phase along with three phase I see it as a direct violation of 110.3(B).

On the other hand I often see disconnects and feed through breakers with instructions for use with both single and three phase.

Usually they will say for single phase or DC use the two outer poles.

IMO installing a three phase panel that is only tagged with a 3 phase label on a single phase supply is both an NEC violation and hack work.

It is likely to lead to overloaded neutrals or single phased motors when someone adds three phase MWBCs or other three phase loads to a panel that is tagged as three phase but is not.
 
I am still trying to figure out how jumpering all three bus bars together would be against any manufacturer's design (as long all other conditions are met). If someone is putting 2 and 3 pole breakers into this panel they are not qualified to perform the work.

Most single phase panels say something like 120/240V 3-wire. Would you accept any 3-wire device even if it is only wired with 2 conductors. How else would you distribute power to 2 wire loads?


edit: complete my thoughts
 
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jim dungar said:
I am still trying to figure out how jumpering all three bus bars together would be against any manufacturer's design (as long all other conditions are met).
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I do not see that as relevant, if the panel is not labeled as suitable for single phase or does not show which busses to jump together IMO it is a violation of 110.3(B) to do so.


If someone is putting 2 and 3 pole breakers into this panel they are not qualified to perform the work.
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Point taken and normally I would be on that bandwagon.

However if you look at a panels labeling and all it says is it is a 3 phase panel I don't think many qualified people will open the cover to verify is in fact supplied with three phase.

Most single phase panels say something like 120/240V 3-wire. Would you accept any 3-wire device even if it is only wired with 2 conductors. How else would you distribute power to 2 wire loads?
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I am sorry Jim I do not understand that last question.

But I have one for you can I install a 3 phase breaker in a single phase panel?
 
Bob,

If you have a 240V 2-wire group of loads fed by a 2-wire transformer, what equipment would you use to feed them? All of the single-phase panels I see are rated as 120/240V 3-wire.

If the customer has a single 120V 2-wire output from an emergency lighting source what piece of equipment should be used to feed 42 circuits?

My suggestion is to ask the manufacturer, not just pass judgment on the limited label information.
 
408.3(E) Phase Arrangement. The phase arrangement on 3-phase buses shall be A, B, C from front to back, top to bottom, or left to right, as viewed from the front of the switchboard or panelboard. The B phase shall be that phase having the higher voltage to ground on 3-phase, 4-wire, delta-connected systems. Other busbar arrangements shall be permitted for additions to existing installations and shall be marked.
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That will be tough to comply with when there are only two or no 'phases' available. ;)
 
jim dungar said:
Bob,

If you have a 240V 2-wire group of loads fed by a 2-wire transformer, what equipment would you use to feed them? All of the single-phase panels I see are rated as 120/240V 3-wire.

If the customer has a single 120V 2-wire output from an emergency lighting source what piece of equipment should be used to feed 42 circuits?
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Well the inverter I wired at a recent job had it's own IEC style din rail mounted SP 20 amp breakers.

It would not even cross my mind to use a typical panel or this unless it was listed and labeled for this use.

My suggestion is to ask the manufacturer, not just pass judgment on the limited label information.
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And my suggestion is still do not to do it. :)

Jim I understand that it may not be a safety issue, but it is not up to us in the field to decide that, we must use the equipment as intended.

Yes you bring up an interesting question but the solution must remain within the NEC we can not simply decide its safe. (even if it is)

As far as the OP we are still stuck with 408.3(E)
 
Bob,

Your answers seem to be based on "I don't like it".

IMO, 408.3 only applies to equipment used on polyphase systems.

All I ever said was to check with the manufacturer not just assume based on appearances.

According to the Square D FAQs:
Question: Can we make a 120 volt only NQOD panelboard?
Answer: We can make a 120 volt only panelboard as a special. It can be main lug or main breaker type providing that a 1 pole breaker is available for use in the application. The bus bars in a 1 phase NQOD interior will be jumpered to create one continuous bus.
 
This is common practice in the trailer park I live in. All the hook-ups are 120v. So, when ever a new trailer comes in they put jumpers between the phase lugs. Nobody is allowed to have 240v appliances because each lot is limited to 40A. The whole park (85 units) runs off one meter and service panel.
 
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