EEJaime
Electrical
- Jan 14, 2004
- 536
I am being asked this question and instinctively I thought I new the answer, but in trying to back it up with a code reference, I am having difficulty locating a specifically applicable code section.
I am using the 2001 California Electrical Code, (1999 NEC with California amendments). This is being used because it was the code in effect when the project went through plan check.
I have an existing customer owned 4.16kV/3ph distribution system in an airport terminal. The system uses a fusible switch lineup to feed various substations throuhout the space. When the designer replaced some existing substations with larger ones he basically duplicated the existing layout.
I have two substations, one each with a 1500kVA, and 2000kVA Transformer, Delta-Wye with a 480Y/277V/3ph/4w secondary distribution board. When I design this type of system, I always specify a switch on the incoming primary feed. An air switch or SF6 depending on the facility. In this case however we indicate these substations without a primary disconnect switch. The feed to it is protected at the Main Distribution Switchboard by a Fused Switch, sized per CEC.
My question is, am I required to have a local disconnect switch on the incoming primary feeder before the transformer?
And if I am required to have this, where in the CEC is this called out. Can the feeder OCP device suffice? Or is a local disconnecting means necessary. The substation is remote from the distribution switchboard.
I am drawing a blank.
Any assistance in pointing me in the right direction will be appreciated. Thank you in advance for your input.
I am using the 2001 California Electrical Code, (1999 NEC with California amendments). This is being used because it was the code in effect when the project went through plan check.
I have an existing customer owned 4.16kV/3ph distribution system in an airport terminal. The system uses a fusible switch lineup to feed various substations throuhout the space. When the designer replaced some existing substations with larger ones he basically duplicated the existing layout.
I have two substations, one each with a 1500kVA, and 2000kVA Transformer, Delta-Wye with a 480Y/277V/3ph/4w secondary distribution board. When I design this type of system, I always specify a switch on the incoming primary feed. An air switch or SF6 depending on the facility. In this case however we indicate these substations without a primary disconnect switch. The feed to it is protected at the Main Distribution Switchboard by a Fused Switch, sized per CEC.
My question is, am I required to have a local disconnect switch on the incoming primary feeder before the transformer?
And if I am required to have this, where in the CEC is this called out. Can the feeder OCP device suffice? Or is a local disconnecting means necessary. The substation is remote from the distribution switchboard.
I am drawing a blank.
Any assistance in pointing me in the right direction will be appreciated. Thank you in advance for your input.