Sizing neutral in Feeder
- Thread starter wmeek
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Re: Sizing neutral in Feeder
I was aslo wanting to know about the grounding of the water pipe, gas pipe, and the structual steel. This particular job is a Lease space. The Main Service is 120/240 3 Phase( Power Company )that has no disconnect, but the neutral is bonded to the ground rod for the whole service to the building.
I have a Nema3 200a 1 Phase Disconnect outside, and a 200 A panel inside the lease space.Do I need to run the grounds (#4)to the inside panel or do they have to go to the Outside disconnect.
Also does the neutral and ground tie together at the outside disconnect.
Thanks
I was aslo wanting to know about the grounding of the water pipe, gas pipe, and the structual steel. This particular job is a Lease space. The Main Service is 120/240 3 Phase( Power Company )that has no disconnect, but the neutral is bonded to the ground rod for the whole service to the building.
I have a Nema3 200a 1 Phase Disconnect outside, and a 200 A panel inside the lease space.Do I need to run the grounds (#4)to the inside panel or do they have to go to the Outside disconnect.
Also does the neutral and ground tie together at the outside disconnect.
Thanks
highkvoltage
Senior Member
Re: Sizing neutral in Feeder
What is going to be operating in this leased space? AC units, microwave, ect. If you do not know I would not down size the neutral. Yes the equipment grounding conductor has to go back to the service disconnect. From the disconnect you would have 4 wires. In the panel you would not bond the neutral (grounded conductor) to the equipment grounding conductor. This is called a isolated neutral. You can only bond these at the point of the service disconnect. If this is a trailer you would have to bond the frame and water lines to the grounding system. I personally would do this at the disconnect.
What is going to be operating in this leased space? AC units, microwave, ect. If you do not know I would not down size the neutral. Yes the equipment grounding conductor has to go back to the service disconnect. From the disconnect you would have 4 wires. In the panel you would not bond the neutral (grounded conductor) to the equipment grounding conductor. This is called a isolated neutral. You can only bond these at the point of the service disconnect. If this is a trailer you would have to bond the frame and water lines to the grounding system. I personally would do this at the disconnect.
highkvoltage
Senior Member
Re: Sizing neutral in Feeder
Also the gas line. The grounding conductor would be #4.
Also the gas line. The grounding conductor would be #4.
highkvoltage
Senior Member
Re: Sizing neutral in Feeder
You can reference the articles 220,230 and 250 in the 2002 NEC. Also appnex D.
You can reference the articles 220,230 and 250 in the 2002 NEC. Also appnex D.
- Location
- Bremerton, Washington
Re: Sizing neutral in Feeder
The minimum size of the grounded neutral conductor is the larger of:
1. the calculated size per 220 (78 amps
2. Section 250.66
250.66 is based on the size of the ungrounded service entrance conductors -copper or aluminum.
The size of the GEC depends on the electrode being connected. For a ground rod the largest is 6 AWG copper.
The GEC terminates to the service disconnecting meants where the main bonding jumper is installed.
The minimum size of the grounded neutral conductor is the larger of:
1. the calculated size per 220 (78 amps
2. Section 250.66
250.66 is based on the size of the ungrounded service entrance conductors -copper or aluminum.
The size of the GEC depends on the electrode being connected. For a ground rod the largest is 6 AWG copper.
The GEC terminates to the service disconnecting meants where the main bonding jumper is installed.
Re: Sizing neutral in Feeder
What I am up against, is a 120/240 3 phase service on a commercial building, that has no service disconnect.The neutral is grounded in the gutter to a ground rod. I am not sure i need to bond my neutral in my disconnect, which would be a Feeder Disconnect. Also how would I bond the water pipe, gas pipe and building steel within my lease space. Would they need to go back to the disconnect or the panel in the lease space.THANKS
What I am up against, is a 120/240 3 phase service on a commercial building, that has no service disconnect.The neutral is grounded in the gutter to a ground rod. I am not sure i need to bond my neutral in my disconnect, which would be a Feeder Disconnect. Also how would I bond the water pipe, gas pipe and building steel within my lease space. Would they need to go back to the disconnect or the panel in the lease space.THANKS
- Location
- Massachusetts
Re: Sizing neutral in Feeder
What's up with a service with no disconnect?
What's up with a service with no disconnect?
Re: Sizing neutral in Feeder
It is an old strip center. The power comes from the weather head to a CT can and to a 8x8x8' gutter. There are several meters and Disconnects for other lease spaces. the service is bonded in gutter to ground rod. Water pipe is grounded as well. this particular strip center shares one water meter.
It is an old strip center. The power comes from the weather head to a CT can and to a 8x8x8' gutter. There are several meters and Disconnects for other lease spaces. the service is bonded in gutter to ground rod. Water pipe is grounded as well. this particular strip center shares one water meter.
- Location
- Massachusetts
Re: Sizing neutral in Feeder
Those disconnects are the service disconnects, the one you are adding is a service disconnect.
You can only have up to six of these.
I am also curious why it hits a CT can and then meters again (Double Metering) hopefully the POCO is not still reading the CT meter.
As for bonding you should take a look at this post.
Bonding Multiple Service Disconnects
Those disconnects are the service disconnects, the one you are adding is a service disconnect.
You can only have up to six of these.
I am also curious why it hits a CT can and then meters again (Double Metering) hopefully the POCO is not still reading the CT meter.
As for bonding you should take a look at this post.
Bonding Multiple Service Disconnects
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