Maybe im too lazy but seeing you all probably know this I have to ask quick. Isnt there some sort of distance rule that when you install a sub panel so many limeted feet from the main breaker panel that you do not have to seperate the ground and neutral connections? thanks, is it in the code?
subpanel seperation
- Thread starter bond
- Start date
- Status
- Location
- Massachusetts
Re: subpanel seperation
If a panel does not contain a service disconnecting means the neutrals and grounds must be separated. The only exception to this is a separate building or structure fed from a common service.
It is possible to have two or more service disconnecting means, a common example is two 200 amp main breaker panels fed from one meter.
In this case both panels contain service disconnects and both will have the the neutrals and equipment grounding conductors bonded.
If a panel does not contain a service disconnecting means the neutrals and grounds must be separated. The only exception to this is a separate building or structure fed from a common service.
It is possible to have two or more service disconnecting means, a common example is two 200 amp main breaker panels fed from one meter.
In this case both panels contain service disconnects and both will have the the neutrals and equipment grounding conductors bonded.
- Location
- Lockport, IL
- Occupation
- Retired Electrical Engineer
Re: subpanel seperation
I agree with Bob. If there is a sub-panel that gets power from a main panel, the N and G are separated. Distance means nothing.
I agree with Bob. If there is a sub-panel that gets power from a main panel, the N and G are separated. Distance means nothing.
bphgravity
Senior Member
- Location
- Florida
Re: subpanel seperation
If the main panel feed to the sub panel is with a metallic raceway, what would be the point of separating the grounded and bondng conductors?
If the main panel feed to the sub panel is with a metallic raceway, what would be the point of separating the grounded and bondng conductors?
- Location
- Massachusetts
Re: subpanel seperation
If we bond at both ends of the raceway the raceway is a now a a neutral conductor. Any loose joints in the raceway could be a source of electrical shock or heating.
cripple
Senior Member
- Location
- Santa Fe, New Mexico
Re: subpanel seperation
The bonding the of the neutral conductor and the equipment grounding conductor is prohibited on load side of the of the service in Section 240.24 and only permitted in Section 250.32(D). By bonding the equipment grounding conductor to the neutral coductor as you asked would violate Section 250.6, 250.142, 300.3 and 310.4.
Some panelboards incorporate neutrals factory bonded to the frame or enclosure and are list and labeled ?Suitable Only For Use As Service Equipment, this permits the equipment grounding conductor to be terminated to the neutral buss per Section 250.142.
Other panelboard with the neutral buss isolated from the frame or enclosure will be list and labeled as Suitable For Use As Service Equipment, this type of panelboards will come with a bonding screw or strap which is supplied by the manufacture. This type of panel can be used as subpanels when feed from the service panel, without the use of the bonding jumper as required per Section 250.24(A)(5).
The bonding the of the neutral conductor and the equipment grounding conductor is prohibited on load side of the of the service in Section 240.24 and only permitted in Section 250.32(D). By bonding the equipment grounding conductor to the neutral coductor as you asked would violate Section 250.6, 250.142, 300.3 and 310.4.
Some panelboards incorporate neutrals factory bonded to the frame or enclosure and are list and labeled ?Suitable Only For Use As Service Equipment, this permits the equipment grounding conductor to be terminated to the neutral buss per Section 250.142.
Other panelboard with the neutral buss isolated from the frame or enclosure will be list and labeled as Suitable For Use As Service Equipment, this type of panelboards will come with a bonding screw or strap which is supplied by the manufacture. This type of panel can be used as subpanels when feed from the service panel, without the use of the bonding jumper as required per Section 250.24(A)(5).
bphgravity
Senior Member
- Location
- Florida
Re: subpanel seperation
But isn't this what we do between a meter enclosure and a main serivce disconnect? Both enclosures are bonded to the service grounded conductor and a metallic raceway can be used between the two.
- Location
- Illinois
- Occupation
- retired electrician
Re: subpanel seperation
Bryan,
Don
[ October 12, 2004, 01:29 PM: Message edited by: don_resqcapt19 ]
Bryan,
For some unknown reason electricity knows if it is on the line or load side of the service disconnect and only chooses to cause problems with parallel grounded conductor paths on the load side of the service disconnect.
Don
[ October 12, 2004, 01:29 PM: Message edited by: don_resqcapt19 ]
- Location
- Massachusetts
Re: subpanel seperation
My question would be;
Why is double bonding allowed on the supply side?
Not why isn't double bonding allowed on the load side.
IMO both situations are potential trouble.
But I guess Don has explained the reason for the different rules.
[ October 12, 2004, 01:42 PM: Message edited by: iwire ]
Yes of course, I am aware of that.
My question would be;
Why is double bonding allowed on the supply side?
Not why isn't double bonding allowed on the load side.
IMO both situations are potential trouble.
But I guess Don has explained the reason for the different rules.
[ October 12, 2004, 01:42 PM: Message edited by: iwire ]
bphgravity
Senior Member
- Location
- Florida
Re: subpanel seperation
Yes I agree, that is the better question.
- Status