I-Line Breakers

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kbsparky

kbsparky

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Delmarva, USA
I have a customer whose main service panel is a delta 3 phase 240 Volt 600 Amp I-Line panel (with the High-leg)

We want to install a feeder from there to a new warehouse on the premises.

The breaker needed would be a FA32100. However, we may have available a 480 Volt FA34100 or 600 Volt FA36100 to use instead.

Is there any reason why we could not use the higher-rated breakers on this application?
 
I have a customer with several 120/208 square d buss ducts. The 480 buss plugs are more readily available (stock item at the supply house), so that's why we normally use on their site. Nothing wrong with it. You can use a 480 sidearm disconnect on a residential air conditioner if you wanted to also. It's just a bit of a waste of money, is all.
 
You might have to use the 480 volt rated breaker if the available fault current is greater than 10kA. That is the rating for the 240 volt breaker, the 480 volt breaker is rated at 25kA at 240 volts and 18kA at 480 volts.
See page 9 of this document.
Don
 
we don't see a lot of I-lines around here, but after reading the document that don cited, it appears that the I-line panel in general is rated for anything upto 480V, is that correct?

I didn't notice any of the panelboards/busbar information specifying voltage, just amperage.

That's nice to know.

Thanks
 
don_resqcapt19 said:
You might have to use the 480 volt rated breaker if the available fault current is greater than 10kA. That is the rating for the 240 volt breaker, the 480 volt breaker is rated at 25kA at 240 volts and 18kA at 480 volts.
See page 9 of this document.
Don
Click to expand...
An interesting observation, Don. The utility transformer sits just outside of that I-Line panel, and I'll bet a dollar to a donut you are correct. I'll give the utility a call and ask about the available fault current and size of that transformer before purchasing a breaker for the feeder to the new building.

We might even have to upgrade to a KA type breaker if the fault current is high enough.
 
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Can the 240V breaker even be used on a high leg system?

When they say a breaker is rated at 240V, I'm not sure if that means line-line voltage, or line-ground??
 
The Square D I-line breaker is fully rated at 240V to ground.

This is confirmerd by its nameplate that only lists a single voltage (i.e. 240V) rather than two voltages separated by a slash (i.e. 120/240V).
 
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