radug
Electrical
- May 23, 2007
- 105
Hello,
One client is requesting for the incomer of a MV gas insulated metal enclosed switchgear (arc resistant), to include two grounding switches: one in the incoming cable connection side and another one being the usual 3-position-disconnector/grounding switch that is located between the circuit breaker and the busbar. Being the circuit breaker non-withdrawable because of the SF6 gas insulation of the cubicle, I see no point in this additional grounding switch in the cable connection side. I have been checking different manufacturers and have not been able to locate anyone offering this.
Someone came across the same requirement? Which would be the purpose? Because with the circuit breaker of the fixed type and no maintenance required, I cannot see any advantange of including this grounding switch. Is this any standard requirement in ANSI/NEMA/UL/IEEE world? Something in NESC or NFPA 70E? Some utility practice, perhaps?
Best regards, radug.
One client is requesting for the incomer of a MV gas insulated metal enclosed switchgear (arc resistant), to include two grounding switches: one in the incoming cable connection side and another one being the usual 3-position-disconnector/grounding switch that is located between the circuit breaker and the busbar. Being the circuit breaker non-withdrawable because of the SF6 gas insulation of the cubicle, I see no point in this additional grounding switch in the cable connection side. I have been checking different manufacturers and have not been able to locate anyone offering this.
Someone came across the same requirement? Which would be the purpose? Because with the circuit breaker of the fixed type and no maintenance required, I cannot see any advantange of including this grounding switch. Is this any standard requirement in ANSI/NEMA/UL/IEEE world? Something in NESC or NFPA 70E? Some utility practice, perhaps?
Best regards, radug.
