240 volt loadcenter wired 120

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augie47

augie47

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Is it a violation to wire a 120/240 loadcenter with 120 volt supply alone.
(jumping Phase A & B line terminals) ? (UPS output is 120 volt only)
There might be a wire termination violation on the line lugs (due to the jumper) and the factory label is 240/120, but it seems the only reasonable way to handle the UPS output.
 
augie47 said:
There might be a wire termination violation on the line lugs (due to the jumper)
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Hit a wire nut or polaris first and take one wire to each lug.

How many amps at 120V do you have?
 
augie47 said:
Is it a violation to wire a 120/240 loadcenter with 120 volt supply alone.
(jumping Phase A & B line terminals) ? (UPS output is 120 volt only)
There might be a wire termination violation on the line lugs (due to the jumper) and the factory label is 240/120, but it seems the only reasonable way to handle the UPS output.
Click to expand...

The neutral bar is limited to that of a single line, so there should not be problem if you feed this with a 1 pole breaker no higher than the panel rating.
 
Still wondering the VA of this thing. The only 120V UPS's I've seen fit under your desk and don't require a down stream panel.
 
I've often wondered if it would be OK to feed a sub-panel with a "hot" and a neutral (neutral connected to B phase) and then feed dispensers at a gas station out of this panel so you will have switching neutral breakers by just using 2-pole breakers instead of a special switched neutral breaker. Since the overcurrent in the neutral would trip the hot, I don't see a problem there.

Comments?
 
If this is done in a PV-supplied panelboard, a warning sign must be posted to avoid installing two circuits sharing a neutral, but I don't know of a requirement for a system supplied by a UPS. I didn't look though. :D
 
augie47 said:
Is it a violation to wire a 120/240 loadcenter with 120 volt supply alone.
(jumping Phase A & B line terminals) ? (UPS output is 120 volt only)
There might be a wire termination violation on the line lugs (due to the jumper) and the factory label is 240/120, but it seems the only reasonable way to handle the UPS output.
Click to expand...
It violates 408.58 if the manufacturer has labeled it a 120/240 panel.
 
Smart $ said:
It violates 408.58 if the manufacturer has labeled it a 120/240 panel.
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I think you should read that section again. This section pertains to the manufacturer and not the installer.

Also, it would be good if people who use the '08 as a reference say so, as most of us will not refer to the '08 for years to come.


P.S.
I do not see how this would not be permitted other than the fact that there is a double tap in one of the lugs - which may be permitted - look on the panel label.
 
Pierre C Belarge said:
I think you should read that section again...
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Rather than read that section again, let's focus on the topic at hand and the 2005 NEC as you implied...
408.30 General. All panelboards shall have a rating not less than the minimum feeder capacity required for the load calculated in accordance with Article 220. 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 and with the manufacturer?s name or trademark in such a manner so as to be visible after installation, without disturbing the interior parts or wiring.
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That is to say, IMO, if it is marked 120/240, it can only be used as a 120/240 panelboard. Do you interpret this differently?

This paragraph changes in the 2008 NEC.
 
Smart $ said:
That is to say, IMO, if it is marked 120/240, it can only be used as a 120/240 panelboard. Do you interpret this differently?

This paragraph changes in the 2008 NEC.
Click to expand...

408.30 General. All panelboards shall have a rating not less than the minimum feeder capacity required for the load calculated in accordance with Article 220. 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 and with the manufacturer?s name or trademark in such a manner so as to be visible after installation, without disturbing the interior parts or wiring.
Click to expand...

This only says that the panelboards shall be marked for the voltage for which they are designed. It does not say they must be supplied by that voltage. A device may be rated for 600 volts but that does not mean we have to supply it with 600 volts. That's MO. FWIW
 
Dennis Alwon said:
This only says that the panelboards shall be marked for the voltage for which they are designed. It does not say they must be supplied by that voltage. A device may be rated for 600 volts but that does not mean we have to supply it with 600 volts. That's MO. FWIW
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That gets my vote to.
 
Dennis Alwon said:
This only says that the panelboards shall be marked for the voltage for which they are designed. It does not say they must be supplied by that voltage. A device may be rated for 600 volts but that does not mean we have to supply it with 600 volts. That's MO. FWIW
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The 120/240 marking indicates a voltage system, and a commonly used one at that. This is not the same as a maximum voltage rating, such as 600 Volts [...maximum].

If we use your logic, a 120/240 panelboard could be used for 24 VAC...!?!?!?!
 
Smart $ said:
The 120/240 marking indicates a voltage system, and a commonly used one at that. This is not the same as a maximum voltage rating, such as 600 Volts [...maximum].

If we use your logic, a 120/240 panelboard could be used for 24 VAC...!?!?!?!
Click to expand...

And why not?

The slash rating (120/240) says the maximum voltage line-ground and the maxiumum voltage line-line that the panel is rated for.
 
Smart $ said:
The 120/240 marking indicates a voltage system, and a commonly used one at that. This is not the same as a maximum voltage rating, such as 600 Volts [...maximum].

If we use your logic, a 120/240 panelboard could be used for 24 VAC...!?!?!?!
Click to expand...

If we use your logic, that panel can't be used, say, for an apartment, at 120/208v 1 ph. (Building with a 208Y/120 volt, 3 ph service) Can you tell me that isn't legal?
 
jim dungar said:
And why not?

The slash rating (120/240) says the maximum voltage line-ground and the maxiumum voltage line-line that the panel is rated for.
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It's not the voltage rating. It's the inclusion of the word "SYSTEM" in the rating. It is designed for a one-pole/two-pole, 3-wire SYSTEM.

Regardless, I could care less either way. Yes, it can be done safely. I am simply pointing out a possible violation, be it subject to interpretation. Yet, wouldn't you agree some type of permanent indication to that effect should be required...??? What happens if the next guy in isn't aware it is connected as desired and pulls/connects a mwbc...???


I would really like to know what manufacturers and listing agencies have to say on the issue.
 
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