Breaker Voltage Ratings

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rruiz642

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Hello,

I'm currently deployed at a US base in SouthWest Asia. I don't have enough electrical experience to list the problems with the following installations, but hopefully I can get some enlighting feedback...thanks in advance.

1) Installed breakers and panels are rated for 240/415. Incoming power is 120/208. Will the advesely affect the breaker performance?

2) Bristish Standard plugs (BS 1365) use one leg @ 220V, a neutral and a ground. Installation is American 220v with two legs @ 208V (ph to ph) and a ground. This was a result of poor specifications in the contract and poor workmanship. Question: will this normally affect the load (bathroom appliances) not to work or will this typically burn up their motors if they call for 220-240v on one leg and a neutral on the other?
 
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jim dungar

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Wisconsin
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PE (Retired) - Power Systems
A 120/208V rating means the breaker is only ated for 120V to ground and 208V phase to phase. These breakers should not be used on your 240/415 system.

During any arc clearing operation the breaker may flash over creating a line to ground or a line to line fault.
 
hmspe

hmspe

Senior Member
Location
Temple, TX
Occupation
PE
jim dungar said:
A 120/208V rating means the breaker is only ated for 120V to ground and 208V phase to phase. These breakers should not be used on your 240/415 system.
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Jim, You might want to read the OP again. I think he said that it's 240/415 rated equipment used at 120/208 supply voltage. If that's the case there should be no problem with the breakers.

As to the rest of the installation, in my opinion it is not safe. The standard British plug configuration expects a certain pin to be at essentially 0 volts to ground. This is similar to the use of a polarized, two pin plug for a lamp in the USA, so that the threaded part of the lamp base is connected to the neutral (so that when the lamp is changed you don't have 120V to ground in a place that's easy to touch). With the configuration rruiz642 posted , the equipment's conductor which the manufacturer expected to be at 0 volts to ground will instead be at 120 volts to ground. Depending on the age, condition, and design of the equipment that could be very dangerous.

Whether equipment designed for 240 volts will run properly at 208 volts depends on the equipment.

Martin
 
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rruiz642

Member
Thanks

Thanks

yes, 120/208 is the supply voltage...thanks for the good advice.

Much appreciated!

Richard
SouthWest Asia
 
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