Temp power

kwired

Electron manager
Location
NE Nebraska
210.8 should be amended to only require (RCD) UL Class B GFCI protection (30ma) for 120/240V single phase 30-50A receptacles. As most are actually 'feeders' in a sense. A 5ma ground-fault on a 120V RV, food truck or spider box receptacle will take out the 'feeder' GFCI before the GFCI receptacle the problem load is plugged into, causing potentially a much larger hazard.
I put a old hot tub 50A GFCI on my RV receptacle years ago and noticed that when a GFCI tries to trip the main goes instead.
210.8 is supposed to be all about personnel protection, which is what class A GFCI is about. That said, I think class A probably should mostly only apply to swimming pools and maybe bathrooms or similar areas and class B to most everything else.

Just a question in passing from that Brit again.
I didn't think you used 250Vac over there?
Or is that just the nominal voltage rating of the receptacle?
Yes 120, 208 and 240 are nominal system voltages, 125 and 250 are common nominal device ratings.

Then when you get into 277 and 480 the system volts and devices are all typically rated 227 and 480 - makes sense right?
 

Besoeker3

Senior Member
Location
UK
Yes 120, 208 and 240 are nominal system voltages, 125 and 250 are common nominal device ratings.

Then when you get into 277 and 480 the system volts and devices are all typically rated 227 and 480 - makes sense right?
Yes, thank you for that.
 

Ohms law

Senior Member
Location
Sioux Falls,SD
Just a question in passing from that Brit again.
I didn't think you used 250Vac over there?
Or is that just the nominal voltage rating of the receptacle?
Rating of receptacle.

240/120 single phase for residential and typical for temp power for small events. Our neutral for single phase is derived from tapping the center of of a winding known as a split phase system.

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Besoeker3

Senior Member
Location
UK
Rating of receptacle.

240/120 single phase for residential and typical for temp power for small events. Our neutral for single phase is derived from tapping the center of of a winding known as a split phase system.
Yes, thank you. I was aware of that. My dear wife is from Georgia. Many of her gadgets were rated for 120V and not rated for use on our 230V 50Hz system.
 

jap

Senior Member
This year the inspector required GFCI protection for 50 amp 250v receptacles so when we turned it all on, every truck was tripping the GFCI breakers. All the trucks had neutrals and grounds terminated under common bars. Needless to say we didn't have material to fix this, and all these folks had suicide cords. I had to yell at a guy and pull a cord end away from him because he was about to touch the Male prongs. We provide 50amp female receptacles.

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Hmmm.... sounds like just a couple of good reasons for the new rule doesn't it ? :)


JAP>
 
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