Many do it yourselfers in my area are replacing thier standard meter sockets with a combo meter socket. 200a normal switch and 100a generator switch. The problem I have is that they still only have the normal 3 conductor service entrance cable going to the inside panel, where the grounded and grounding conductors are all joined on the same strip. Is this not a code violation or is there some exception? I don't think so. To be compliant, don't they have to upgrade to 4 conductor se cable and separate the load grounded and grounding conductors in the inside panel?
generator connections
- Thread starter stader
- Start date
- Status
- Location
- Bremerton, Washington
- Occupation
- Master Electrician
Re: generator connections
If the neutral is not transferred, then a generator is not a separately derived system. The neutral to case bond jumper is not installed in the generator, if hard wired 3 wire wire?connection plus equipment grounding conductor is used.
If the neutral is not transferred, then a generator is not a separately derived system. The neutral to case bond jumper is not installed in the generator, if hard wired 3 wire wire?connection plus equipment grounding conductor is used.
russ
Senior Member
- Location
- Burbank IL
Re: generator connections
I agree that the grounded conductor, the bond, and the grounding electrode conductor should be moved from the panel in the house to the new main disconnect outside. 250.24(1)
I agree that the grounded conductor, the bond, and the grounding electrode conductor should be moved from the panel in the house to the new main disconnect outside. 250.24(1)
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: generator connections
I agree once after the main means of disconection the neutral and grounds are to be kept seprate, which is now the new 200 amp breaker at the meter.
250.24 (A) (5)
Also I question using a 100 amp transfer switch on a 200 amp service unless it has a 200 amp pass through rating or the service has only a 100 amp calculated load.
230.79 I think.
The other thing is Now that we have to keep the neutrals and grounds seprate at the generator too or a 4-pole transfer switch will be needed. other wise there will be a parallel path on the neutral from the generator to the meter.
Ed had a diagram of this he posted a while back maybe someone can post a link to it again.
[ December 21, 2003, 10:54 PM: Message edited by: hurk27 ]
I agree once after the main means of disconection the neutral and grounds are to be kept seprate, which is now the new 200 amp breaker at the meter.
250.24 (A) (5)
Also I question using a 100 amp transfer switch on a 200 amp service unless it has a 200 amp pass through rating or the service has only a 100 amp calculated load.
230.79 I think.
The other thing is Now that we have to keep the neutrals and grounds seprate at the generator too or a 4-pole transfer switch will be needed. other wise there will be a parallel path on the neutral from the generator to the meter.
Ed had a diagram of this he posted a while back maybe someone can post a link to it again.
[ December 21, 2003, 10:54 PM: Message edited by: hurk27 ]
Re: generator connections
I question that your combo device is being used correctly. Is there a transfer switch in the meter base, or are there two switches, one of which must be turned off, and one must be turned on to work? If so, then a backfeed could exist, a major hazard to the linemen trying to restore power.
I question that your combo device is being used correctly. Is there a transfer switch in the meter base, or are there two switches, one of which must be turned off, and one must be turned on to work? If so, then a backfeed could exist, a major hazard to the linemen trying to restore power.
Re: generator connections
Pretend the 3 wires from the generator is a back up service feeder, to the transfer switch.
Nothing needs to change in the existing installation, with the generator being used as a back up. The transfer switch is a transfer switch, it is not a main service switch.
Pretend the 3 wires from the generator is a back up service feeder, to the transfer switch.
Nothing needs to change in the existing installation, with the generator being used as a back up. The transfer switch is a transfer switch, it is not a main service switch.
- Location
- Illinois
- Occupation
- retired electrician
Re: generator connections
Bennie,
I appears that they are adding a 200 amp service disconnect switch at the meter. If so the code will require four wires from the disconnect switch to the panel. The "transfer switch" appears to be a mechanical interlock between the 200 amp service disconnect switch and the 100 amp generator switch.
Don
Bennie,
I appears that they are adding a 200 amp service disconnect switch at the meter. If so the code will require four wires from the disconnect switch to the panel. The "transfer switch" appears to be a mechanical interlock between the 200 amp service disconnect switch and the 100 amp generator switch.
Don
Re: generator connections
Technically the meter socket is a pull out switch. This changes nothing electrically, that requires four wires to the main panel. Why should the addition of a switch of any kind, make any difference.
The intent of separating the nuetral and equipment ground conductor at a panel is to prevent objectionable current flow. There will be no objectionable current with a 3 wire supply cable.
This is an area that needs to be cleaned up, by applying more details, to the process.
Technically the meter socket is a pull out switch. This changes nothing electrically, that requires four wires to the main panel. Why should the addition of a switch of any kind, make any difference.
The intent of separating the nuetral and equipment ground conductor at a panel is to prevent objectionable current flow. There will be no objectionable current with a 3 wire supply cable.
This is an area that needs to be cleaned up, by applying more details, to the process.
- Location
- Illinois
- Occupation
- retired electrician
Re: generator connections
Bennie,
Don
Bennie,
The meter socket is not listed for use as a switch.
Don
- Location
- Illinois
- Occupation
- retired electrician
Re: generator connections
Bennie,
To prevent parallel paths for the grounded conductor current the code had to separate the grounding and grounded conductors at some point. The point that the code uses in on the line side or within the service disconnect. In some cases it would be possible to bond the grounded conductor and multiple points without creating parallel paths, but to spell out all of the conditions in the code would make the code even harder to understand and comply with. The service disconnect is a convenient point at which this separation can be required. If a service disconnect is added at the meter, the grounded and grounding conductors are required to be separated at the panel by the code rules.
Don
Bennie,
To prevent parallel paths for the grounded conductor current the code had to separate the grounding and grounded conductors at some point. The point that the code uses in on the line side or within the service disconnect. In some cases it would be possible to bond the grounded conductor and multiple points without creating parallel paths, but to spell out all of the conditions in the code would make the code even harder to understand and comply with. The service disconnect is a convenient point at which this separation can be required. If a service disconnect is added at the meter, the grounded and grounding conductors are required to be separated at the panel by the code rules.
Don
Re: generator connections
This is where I am having a problem understanding the definition of a service panel.
Are you saying that when a transfer switch is added on the supply side of a service, the transfer switch becomes the service panel?
You say a panel can't be grounded with the neutral. The service panel is grounded by the neutral.
I don't think the transfer switch changes the definition of a service panel.
There is no such thing as a sub panel. There is no words in the code that says the panel must be supplied by 4 wires and the ground and neutral must be separated.
When there is a parallel path, this procedure will correct the objectionable current problem. When there is no parallel path except the earth, I can not see any code rule that says the neutral and ground must be separated.
There is a lot of holes in the logic of grounding, this is another one. The method to prevent objectionable current flow is a result of one individuals decision.
I will drop this issue for now, it goes no where. When the NEC specifically states that a panel shall have the neutral and ground separated, even if the overcurrent device is a foot away, then I will form another opinion.
This is where I am having a problem understanding the definition of a service panel.
Are you saying that when a transfer switch is added on the supply side of a service, the transfer switch becomes the service panel?
You say a panel can't be grounded with the neutral. The service panel is grounded by the neutral.
I don't think the transfer switch changes the definition of a service panel.
There is no such thing as a sub panel. There is no words in the code that says the panel must be supplied by 4 wires and the ground and neutral must be separated.
When there is a parallel path, this procedure will correct the objectionable current problem. When there is no parallel path except the earth, I can not see any code rule that says the neutral and ground must be separated.
There is a lot of holes in the logic of grounding, this is another one. The method to prevent objectionable current flow is a result of one individuals decision.
I will drop this issue for now, it goes no where. When the NEC specifically states that a panel shall have the neutral and ground separated, even if the overcurrent device is a foot away, then I will form another opinion.
- Location
- Massachusetts
Re: generator connections
Bennie explain to me how I could run just 3 wires in from the 200 amp service disconnect and comply with this.
Bennie explain to me how I could run just 3 wires in from the 200 amp service disconnect and comply with this.
You may not agree with it but it is code and it works fine.
ryan_618
Senior Member
- Location
- Salt Lake City, Utah
Re: generator connections
250.24(A)(5)
- Status