Service Disconnect

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Smash

Senior Member
200A residential service outdoor meter underground service. Only one panel for the home in the basement.200A main breaker 40 pos. The load side of the meter travels through the garage aprox 40' Im putting in a 200A service disconnect nippled to the outdoor meter. Why once this disconnect is installed does the main panel in basement now become a sub panel. I understand insulated neutral and isolated ground is required within the wire (SER) for instance. (I'm actually running EMT for this job) but not sure why seperate in the load center. Suppose the panel was directly on the opposite side of the wall but the customer still wanted a disconnect still a sub panel ?
Also does the service disconnect require two grounding sources as well ?
 

iwire

Moderator
Staff member
Location
Massachusetts
All I can say is because the NEC says so.

The service entrance conductors stop at first disconecting means and anything beyond that point is a feeder or branch circuit conductors both of which require neutrals isolated from ground when used.

Yes you will have to move all your grounding electrode connections to the new service disconnect.
 

kwired

Electron manager
Location
NE Nebraska
The supply side (POCO system) is a multi-grounded system. They have grounding electrodes at nearly every structure. It does create stray voltage issues sometimes because the "neutral" is carrying current, and when a conductor carries current there is a voltage drop across it.

That voltage drop is likely one of the top reasons NEC requires separate grounding conductors past the service disconnect or first disconnecting means of a separately derived system. Though the risks are probably somewhat low for a short nipple between enclosures, you have to draw the line for separation somewhere.

NEC only requires one grounding electrode system for a building or structure. You must use all electrodes mentioned in 250.52(A)(1 thru 7) that are present though. If a water pipe electrode is the only electrode present you must supplement it with another type of electrode - ground rods are most common as they are simple and cost effective.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
First, let me ask if the house and the garage are separate buildings (i.e., not touching each other). That would change all the answers to your questions.

Presuming the house and garage are attached to each other, so that they comprise a single building, then,

  1. You need only one grounding electrode system, and as Bob pointed out it must be connected at the location of the new service disconnecting means.
  2. You need to treat the original "load center" as a sub-panel, meaning that you must keep the equipment grounding conductors and the neutrals separate from each other.
  3. The reason for item 2 is that if the N and G bars are connected at the service and at a panel downstream, then the current that will return to the source via the neutral will have a parallel path in the equipment grounding conductors. Thus, your EMT will carry current all the time, and it should never carry current.
 

Smash

Senior Member
The garage is attached
With all the supply line issues I'm surprised it's not required all the time seperation of grounds & neutrals. Probably only a matter of time. Our code changes like underwear safety first I get it but it's still legal to use quick connects on the back of switches and receptacles. Lost count of how many short or burn. Quick and easy trumps safety. Makes you wonder how much influence big companies who make them have. Even the Sylvania & Phillips of the world making everyone swallow those CFL bulbs now people think LED is another scam. Sorry Sore subject for another day. Still a sparky forum so I can still bitch Did you ever try to explain to a 80 yr old woman she has to have TR receptacles and $40 arc fault breakers, and that her job now costs an extra $200 They think your making it all up, not to kind in this new review world.
our job gets tougher and more expensive to keep up with & plumbers job gets easier materials cheaper sling plastic everywhere flex gas pipe sling it anywhere don't even have to strap it down walls, yet they make even more money. Bastards ahh that felt good. Thx lord knows the little wifey poo don't wanna hear it.
 

kwired

Electron manager
Location
NE Nebraska
The garage is attached
With all the supply line issues I'm surprised it's not required all the time seperation of grounds & neutrals. Probably only a matter of time. Our code changes like underwear safety first I get it but it's still legal to use quick connects on the back of switches and receptacles. Lost count of how many short or burn. Quick and easy trumps safety. Makes you wonder how much influence big companies who make them have. Even the Sylvania & Phillips of the world making everyone swallow those CFL bulbs now people think LED is another scam. Sorry Sore subject for another day. Still a sparky forum so I can still bitch Did you ever try to explain to a 80 yr old woman she has to have TR receptacles and $40 arc fault breakers, and that her job now costs an extra $200 They think your making it all up, not to kind in this new review world.
our job gets tougher and more expensive to keep up with & plumbers job gets easier materials cheaper sling plastic everywhere flex gas pipe sling it anywhere don't even have to strap it down walls, yet they make even more money. Bastards ahh that felt good. Thx lord knows the little wifey poo don't wanna hear it.

Separation of grounds and neutrals beyond service equipment is nothing new, until 2008 NEC it was mostly only allowed to run a single grounded conductor to separate buildings or structures, and everything else needed separate conductors. Then back until 1996 NEC (I think it was 1996) we could still use one conductor on ranges and dryers as neutral and EGC.

Quick connects on receptacles has never been an NEC issue - those items are listed for that purpose, they may not be all that well designed but are listed.

I don't feel CFL's or LED's are a scam. They do use less energy then an incandescent lamp that puts out same amount of light. They may or may not always be worth the investment depending on the conditions of use. If you want to complain about something in this area, complain about how the Department of Energy made standard incandescent lamps somewhat obsolete. They still do have some uses that many feel are better then what is replacing them.

Problem with lighting technology is things are changing fast, where we had same things with minor changes for over 100 years. T12 fluorescent lamps were around since maybe 1940's, maybe were more popular once we got into the 1950's. They stayed mostly the same with only minor increases in efficiency up until 1990's and even into 2000's before T8 started to dominate, but only for a short time, then they kept coming up with something more efficient, but cost was high on most of the new products. Now prices are starting to come down as some of these things are increased in production and sales, until the next new development comes along.

TR receptacles don't require you to know much about electricity to see how those can enhance safety, whether worth the extra component and cost, could be debatable though, but it isn't adding a horrible amount of cost to a new home.

AFCI - the concept is great, the practicality of what is out there meeting that concept is not here yet, the scam is them forcing us to use something that is not ready yet so some big businesses can see some return on their R & D they put into what they do have.
 

jap

Senior Member
Occupation
Electrician
The garage is attached
With all the supply line issues I'm surprised it's not required all the time seperation of grounds & neutrals. Probably only a matter of time. Our code changes like underwear safety first I get it but it's still legal to use quick connects on the back of switches and receptacles. Lost count of how many short or burn. Quick and easy trumps safety. Makes you wonder how much influence big companies who make them have. Even the Sylvania & Phillips of the world making everyone swallow those CFL bulbs now people think LED is another scam. Sorry Sore subject for another day. Still a sparky forum so I can still bitch Did you ever try to explain to a 80 yr old woman she has to have TR receptacles and $40 arc fault breakers, and that her job now costs an extra $200 They think your making it all up, not to kind in this new review world.
our job gets tougher and more expensive to keep up with & plumbers job gets easier materials cheaper sling plastic everywhere flex gas pipe sling it anywhere don't even have to strap it down walls, yet they make even more money. Bastards ahh that felt good. Thx lord knows the little wifey poo don't wanna hear it.


I'm still not sure how the service conductors were ever allowed to run 40' inside the structure without a disconnecting means at or near the closest point of entry.

JAP>
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
The garage is attached
With all the supply line issues I'm surprised it's not required all the time seperation of grounds & neutrals. Probably only a matter of time. ....
That would require an additional conductor from the utility transformer to the service equipment....I don't see that a something that is likely to happen.
 

jap

Senior Member
Occupation
Electrician
That would require an additional conductor from the utility transformer to the service equipment....I don't see that a something that is likely to happen.

And a total rebuild of almost all meter bases which have the neutral lug mounted directly to the enclosure.
I'm with you, I don't see that as likely to ever happen.

JAP>
 

Smash

Senior Member
Separation of grounds and neutrals beyond service equipment is nothing new, until 2008 NEC it was mostly only allowed to run a single grounded conductor to separate buildings or structures, and everything else needed separate conductors. Then back until 1996 NEC (I think it was 1996) we could still use one conductor on ranges and dryers as neutral and EGC.

Quick connects on receptacles has never been an NEC issue - those items are listed for that purpose, they may not be all that well designed but are listed.

I don't feel CFL's or LED's are a scam. They do use less energy then an incandescent lamp that puts out same amount of light. They may or may not always be worth the investment depending on the conditions of use. If you want to complain about something in this area, complain about how the Department of Energy made standard incandescent lamps somewhat obsolete. They still do have some uses that many feel are better then what is replacing them.

Problem with lighting technology is things are changing fast, where we had same things with minor changes for over 100 years. T12 fluorescent lamps were around since maybe 1940's, maybe were more popular once we got into the 1950's. They stayed mostly the same with only minor increases in efficiency up until 1990's and even into 2000's before T8 started to dominate, but only for a short time, then they kept coming up with something more efficient, but cost was high on most of the new products. Now prices are starting to come down as some of these things are increased in production and sales, until the next new development comes along.

TR receptacles don't require you to know much about electricity to see how those can enhance safety, whether worth the extra component and cost, could be debatable though, but it isn't adding a horrible amount of cost to a new home.

AFCI - the concept is great, the practicality of what is out there meeting that concept is not here yet, the scam is them forcing us to use something that is not ready yet so some big businesses can see some return on their R & D they put into what they do have.

No I never thought LEDs were a scam I love them. But that technology has been around since the 70s my problem is why we ever had to go through the CFL stage at all. They were bad light with dimming issues, plus TH e added danger of mercury. Pretty sure we could have skipped that phase and went right to LED. Since clients bought the energy savings of the CFL and hate them, they feel cheated and scammed. Trying to sell them LEDs is that much tougher. They will eventually come around cause is good stuff and getting better. Finally a product that's easier to install never thought I'd see the day.
 

kwired

Electron manager
Location
NE Nebraska
No I never thought LEDs were a scam I love them. But that technology has been around since the 70s my problem is why we ever had to go through the CFL stage at all. They were bad light with dimming issues, plus TH e added danger of mercury. Pretty sure we could have skipped that phase and went right to LED. Since clients bought the energy savings of the CFL and hate them, they feel cheated and scammed. Trying to sell them LEDs is that much tougher. They will eventually come around cause is good stuff and getting better. Finally a product that's easier to install never thought I'd see the day.
LED's from the 70's were only good for indicators and displays for the most part. Even 10 years ago the products on the market for general lighting were not that great, efficient yes, but poor light quality. Now they are just starting to become decent general lighting sources and cost is getting reasonable.

I haven't been all that impressed with many CFL's myself over those years.

CFL's were a bad idea for places that have short run times. Closets, storage rooms, etc. I don't think get near the life as a main room that the light remains on for long periods of time. Every start takes a little life away from the lamp or the lamp driver or both, that is my thought anyway.
 
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