GFCI Breaker Questions

[John McCann]

I'm working on a project in Afghanistan and we have 120/208 supply for the common electrical equipment used here at this site. We were shipped some exercise machines that require 230V/neutral. I plan to feed this equipment from a separate 230/416V power source through a 225A QO Square-D panel that we have on hand using QO GFCI branch circuit breakers, with a current rating of 20 Amps. These single pole GFCIs are rated 120/240V. Will these work for the 230V application? I need clarification on that please! Because this is considered a damp location (tents) we are pushing for the GFCIs. Is personnel protection at 5 milliamps/120 Volts the same as 5 milliamps/230 Volts or does it have to be 2.5 milliamps at 230 Volts (equal power) to obtain the same protection? We are in a very remote area and materials/information considering multi-voltage applications are difficult to collect. Any help here will be apprieciated!

 

[cpal]

Is this system 230V to ground 414V line??

If so the 240/120V breaker would not be listed vor that application. Do they fit in the panel??

 

[mull982]

I'm working on a project in Afghanistan and we have 120/208 supply for the common electrical equipment used here at this site. We were shipped some exercise machines that require 230V/neutral. I plan to feed this equipment from a separate 230/416V power source through a 225A QO Square-D panel that we have on hand using QO GFCI branch circuit breakers, with a current rating of 20 Amps. These single pole GFCIs are rated 120/240V. Will these work for the 230V application? I need clarification on that please! Because this is considered a damp location (tents) we are pushing for the GFCIs. Is personnel protection at 5 milliamps/120 Volts the same as 5 milliamps/230 Volts or does it have to be 2.5 milliamps at 230 Volts (equal power) to obtain the same protection? We are in a very remote area and materials/information considering multi-voltage applications are difficult to collect. Any help here will be apprieciated!

A GFCI looks at current leaving on the hot and returing on the neutral. If there is no ground fault than these two currents sum to zero and the breaker is fine. If there is a ground fault and some current goes to ground then the two currents will no longer sum to zero but will some to zome other positive number. Typically when this number equates to 5ma (amount of ground fault current) the breaker will trip.

With a 230V L-N service such as you stated you have I would think the principal is the same. Ground current is what you are looking to detect so in that sense "current is current" and a value of 5mA should be used to trip the breaker. With that being said as long as the breaker was seeing the hot and neutral current, it should work for this larger L-N voltage.

I'm saying all of this independent of any UL listings or ratings for the breaker used in this application as others mentioned.

 

[cpal]

A
I'm saying all of this independent of any UL listings or ratings for the breaker used in this application as others mentioned.

extract from NEC
I understand that many electricians that are seeking work are going overseas to fix the electrical problems that have endangered our uniformed service personnel. I applaud their effots and wish them well. (I am retired Navy myself). But if this project is for the US Govt. then there is probably a requirment to follow (someones)Code. (I assume) in that case that the following code reference is important. Some one on this site has a tag ine "just because it works doesen't make it right" (or something like that)

240.85 Applications.
A circuit breaker with a slash rating, such as 120/240V or 480Y/277V, shall be permitted to be applied in a solidly grounded circuit where the nominal voltage of any conductor to ground does not exceed the lower of the two values of the circuit breaker?s voltage rating and the nominal voltage between any two conductors does not exceed the higher value of the circuit breaker?s voltage rating.
FPN: Proper application of molded case circuit breakers on 3-phase systems, other than solidly grounded wye, particularly on corner grounded delta systems, considers the circuit breakers? individual pole-interrupting capability.

 

[VxA]

You could likley run a 230V motor on a 208V supply. It will draw slightly more current (run slightly hotter) and also may produce slightly less power. I think most motors (NEMA motors) can run at +/- 10% voltage. If your motor is built with these tolerances, it should be able to run at 208V. It's not what I would call best practice; your motor(s) may burn out prematurely.

Otherwise, installing transformer to step up the voltage would be the way to go if it's possible.