Does the GEC need to be brought to the main service disconnecting means first in order to comlpy with 250.24(A) (1)? Have a retro job where the GEC is currently run to a 300A main breaker panel which before was the first panel after the CT cabinet. Now a service disconnect has been added to the building exterior and that in turn feeds that first panel. Am I wrong in calling that panel now a sub panel? Not a big deal to change it just not sure if it needs to be. Thanks. FWIW this is a 120?240 Delta 3P system.
GEC connection
- Thread starter nizak
- Start date
- Status
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
The gec needs to go to the service- usually the meter or the first disconnect.
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TNGuy81
Member
- Location
- Nashville TN
u mean 120/208??
ericsherman37
Senior Member
- Location
- Oregon Coast
120/240 3 phase would be a Delta setup. 120/208 is usually Wye.
TNGuy81
Member
- Location
- Nashville TN
ahh i see. I have never worked with a 120/240 3 phase before. A 120/240 3 wire yes but not a 3 phase. 120/208Y i have worked with many times. It must be a older system ?? The delta stuff I dont have any experience with, yet.
stevebea
Senior Member
- Location
- Southeastern PA
Yes 120/240 3 Phase Delta is an older system but is still very common in older shops. Beware of high leg when adding 120V circuitry. One of our guys took out 4 cash registers a few years ago when he landed a 120V receptcale circuit on the " stinger " phase.
LarryFine
Master Electrician Electric Contractor Richmond VA
- Location
- Henrico County, VA
- Occupation
- Electrical Contractor
Just a quickie:
In a 240v Delta, the 120/240 section is exactly the same as a typical 120/240v 1ph service. The difference is that there is a third line conductor, which is 240v from each of the other two lines, and an unusable 208v from the neutral.
Think of it as a 120/240v 1ph service "superimposed" on a 240v 3ph Delta service. It's a simple triangular, or Delta, arrangement of three 240v transformer secondaries, and the center tap of one of them is the grounded neutral.
TNGuy81
Member
- Location
- Nashville TN
interesting, and thanks for that info. I have read on them just have not came across one yet in the field.
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