| Author |
Message |
LD (63.224.243.124)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, February 07, 2001 - 8:55 pm: | |
I would appreciate any questions directed to me be posted on a groups site for everyone's benefit, I am posting this direct e-mail
LD
> Given:
> If you where developing a RV park and had the capability to request primary metering from the utility company for your own primary
> distribution system with transformer and a centrally located 120/240 3 wire disconnect panel for simple purposes of sectionalizing.
>
> 1.) Would you use or add a equipment grounding conductor to then 120/240 3 wire feeder from the above sectionalizing disconnect panel to each RV
> pedestal site that includes it's own service disconnect means at the RV site?
>
> 2.) Or would you run the 120/240 3 wire RV feeder to each RV site as a grounded neutral supply conductor and bond each RV pedestal service
> disconnect at point of service near RV site as in 250-130(a) which includes separate ground electrode, bonding jumper and screw.
>
> 3. What are the advantages of equipment grounding over grounding electrode/grounded neutral ? Or vice versa ?
>
> Thanks for your help, enjoy your articles.
120v loads are between the neutral and the phase leg, if you do not separate the ground and neutral after you leave the primary panel,
loss of the neutral will cause return current on the ground, something you don't want particularly because of the metal skin on the RV which is bonded/grounded to your ground. Connect them in the primary panel and isolate them after that-ground rods, etc. are not sufficient to "clear" a ground fault so you must carry a sufficient
size ground to each pedestal.
LD |
John Jewett (Jayjay) (152.163.205.79)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, February 09, 2001 - 10:46 pm: | |
LD, A new installation (of any size) will probably be 4160V 3 Phase 4 wire Primary,and a 120/240 4 wire single phase secondary, through demand metering.From your switch-gear, (through multiple fused disconnect switches) there will be 4 wires to each pedestal. (2 phase legs, one equipment ground, and one grounded conductor (the neutral). The Power Co. and/or the Electrical Inspector may require ground rods at each pedestal. Bonding of the Neutral will occur at the distribution fused disconnects, and at the pedestals ( yes, both places !!) Ground rods are installed specifically to dissipate faults. A 3/4 in. X 8 ft. rod will safely neutralize about 70,000 V AC fault, or 450,000 DC volts of lightning. I hope this helps. In most areas you are going to have to hire an Electrical Enginneer and a Professional Engineer to do the Plans (can be the same person), Schematics, Riser Diagrams, Get the State License etc. Good luck, get out your checkbook, and Cheers...JJ |
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