service Amperage ?

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Old 03-19-10, 11:05 PM
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service Amperage ?

greetings to all,

I was surfing the web in search of an answer to my dilemma when I came upon this site. I surfed around here for a while and found that there is quite a lot of useful info that I hope to take advantage of in the near future. so hopefully you guys can help me, since the 2 electricians that have come to the house have not been able to give me any insight. of course, between both of them they probably only had about 10 years experience. so I'll go easy on them.

on to the dilemma. I'm wanting to find out what service amperage I am getting to the meter. one electrician told me that the size of the meter base will dictate that. so the electrician comes out and looks at the meter base and right away says that I'm getting 100A service. we then move to the service panel which is directly on the opposite side of the wall in the garage. we open the service panel and the main breaker is a double pole 50A. at this point the electrician is dumbfounded. a few days later he comes back with a coworker who is also. how can I have 100A service but only a 50A main breaker? or is the double pole 50A breaker really a 100A breaker?? at this point I'm NOT even sure if I have 100A service. is there a way that I can find out what amperage I'm getting for sure. I'm tired of hearing the same thing from electricians. I've even been to the local hardware chain stores to talk to their electrical experts and they have been no help.

my home was built in '63 and it has the original service panel which is a Square D, QO series. wasn't 60A service last used in the 1940's.

hopefully I can find some help here, I'm running out of options.

TIA

-carlos
 
  #2  
Old 03-20-10, 05:11 AM
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The SIZE of the service entrance WIRE, from the pole to the service panel, determines the maximum amperage capability.
 
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Old 03-20-10, 05:55 AM
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Contact your POCO and have them verify your drop amperage. You can have a 100 amp drop and only protect it at 50 amps, but I don't see why. If they verify you have a 100 amp service, then you could permit and proceed with a panel upgrade.
 

Last edited by chandler; 03-20-10 at 06:38 AM.
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Old 03-20-10, 06:05 AM
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Welcome to the forums.

Originally Posted by quickNOTCH View Post
wasn't 60A service last used in the 1940's.
Not necessarily. My house was built in 1973 and it had a 50a main, limited by the service entrance wires.
 
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Old 03-20-10, 07:36 AM
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How many breaker spaces are in this panel? Remove the cover, do the incoming wires go to the 50? If so you have 50A service, if they go to main lugs you likely have 100. If there are 6 spaces or less you might not even have a main breaker.
at this point the electrician is dumbfounded. a few days later he comes back with a coworker who is also.
Neither one should be sticking their screwdrivers in a box unsupervised.
 
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Old 03-20-10, 07:48 AM
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Your service entrance consists on the wiring from the weatherhead to the meter socket, the meter socket, wiring from the socket to the service panel and the service panel itself. The service entrance conductor size and ratings of the socket and service panel determine your service size. The service lateral, or service drop, is normally sized by the power company according to your load and has little to do with what size service you have. If you have a 50 amp main breaker, you have at most a 50 amp service. If the service was installed in 1963, I can assure you that it is due to be replaced and probably should be upgraded to a modern 100 amp service. This doesn't mean the power company will upgrade the service lateral if the load doesn't warrant it. I don't know where you found your electricians, but you need to keep looking.
 
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Old 03-20-10, 08:21 AM
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Is it possible you have multiple main breakers? Some older style services have a split bus panel where big loads like the range have their own main breaker. This type of panel usually has the large double pole loads in the upper section and the 15A and 20A general purpose loads in the lower section.
 
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Old 03-20-10, 09:35 AM
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Those rating on the meter socket were what the socket was rated to handle up to. You could install a 60 amp service but the socket was good for up to a 100 amp service rating.
 
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Old 03-20-10, 04:52 PM
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Originally Posted by dialer View Post
The SIZE of the service entrance WIRE, from the pole to the service panel, determines the maximum amperage capability.
is this something I can measure myself?
 
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Old 03-20-10, 04:56 PM
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Originally Posted by chandler View Post
Contact your POCO and have them verify your drop amperage. You can have a 100 amp drop and only protect it at 50 amps, but I don't see why. If they verify you have a 100 amp service, then you could permit and proceed with a panel upgrade.
what is POCO? is there a charge for this?
 
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Old 03-20-10, 05:02 PM
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POCO is shorthand for Power Company...as to the charge....dunno..but it should be something they can look up without sending someone...
 
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Old 03-20-10, 05:08 PM
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Service cables should have a size on the outside of the jacket. A typical marking could be like 4/0 AL SE-U.
 
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Old 03-20-10, 05:11 PM
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Originally Posted by sberry27 View Post
How many breaker spaces are in this panel? Remove the cover, do the incoming wires go to the 50? If so you have 50A service, if they go to main lugs you likely have 100. If there are 6 spaces or less you might not even have a main breaker. Neither one should be sticking their screwdrivers in a box unsupervised.
there are 13 spaces in the panel. 2 are double pole, one of which is the main. 5 are tandem, 3 are single pole and the last one is a 30A that takes up to spaces but only has one toggle.

yes, the incoming wires go to main lugs. FROM the main breaker there are 2 wires that come out, where should those go??
 
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Old 03-20-10, 05:17 PM
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Originally Posted by ibpooks View Post
Is it possible you have multiple main breakers? Some older style services have a split bus panel where big loads like the range have their own main breaker. This type of panel usually has the large double pole loads in the upper section and the 15A and 20A general purpose loads in the lower section.
there is a double pole 30A under the 50A main. it has 10ga. red and black wires from it.
 
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Old 03-20-10, 05:20 PM
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Originally Posted by pcboss View Post
Service cables should have a size on the outside of the jacket. A typical marking could be like 4/0 AL SE-U.
I will take a look.
 
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Old 03-20-10, 05:23 PM
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Originally Posted by pcboss View Post
Those rating on the meter socket were what the socket was rated to handle up to. You could install a 60 amp service but the socket was good for up to a 100 amp service rating.
you lost me here boss. can you explain?
 
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Old 03-20-10, 05:34 PM
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BTW, thanks to everyone for the help so far. such quick replies were unexpected.
 
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Old 03-20-10, 05:41 PM
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I may step on pcboss.....but ....

Basically...think of putting tires (meter and socket) rated up to 100mph speeds, on a car that could only go up to 60 (panel and main breaker)?

Well...if you sold more of those tires than any other..they might be cheaper...so you just put them on every car.
 
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Old 03-20-10, 05:48 PM
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yes, the incoming wires go to main lugs. FROM the main breaker there are 2 wires that come out, where should those go??
Actually your service wires should go to the main breaker. Are you saying the service wires go to the lugs? A picture of your box might help. http://forum.doityourself.com/electr...your-post.html
 
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Old 03-20-10, 06:39 PM
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No problem at all Vic. ................................
 
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Old 03-20-10, 09:49 PM
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Originally Posted by ray2047 View Post
Actually your service wires should go to the main breaker. Are you saying the service wires go to the lugs? A picture of your box might help. http://forum.doityourself.com/electr...your-post.html
that is what it looks like to me. they come through the back panel of the service panel. I will get a pic for you tomorrow.
 
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Old 03-20-10, 11:03 PM
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This is sounding more and more like a 100 amp split bus panel. If so, the 50 amp 2 pole breaker is probably the lighting section subfeed main, but a picture certainly would help.
 
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Old 03-20-10, 11:28 PM
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Originally Posted by CasualJoe View Post
This is sounding more and more like a 100 amp split bus panel. If so, the 50 amp 2 pole breaker is probably the lighting section subfeed main, but a picture certainly would help.
Yes, that is what I was thinking when I asked. The 50a breaker sounded wrong for a main breaker. Possible sure but but many 60amp panels were 6 throws or less with no main breaker. Wonder why the two electricians didn't spot that immediately?
 
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Old 03-21-10, 09:36 AM
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Originally Posted by ray2047 View Post
Yes, that is what I was thinking when I asked. The 50a breaker sounded wrong for a main breaker. Possible sure but but many 60amp panels were 6 throws or less with no main breaker. Wonder why the two electricians didn't spot that immediately?
Maybe this could be why (maybe they haven't seen a split bus panel).

since the 2 electricians that have come to the house have not been able to give me any insight. of course, between both of them they probably only had about 10 years experience
This is why I previously said:

I don't know where you found your electricians, but you need to keep looking.
 
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Old 03-21-10, 03:27 PM
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I'm working on the pic. wife has camera with her. should be home a little later.
 
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Old 03-21-10, 03:30 PM
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Originally Posted by ray2047 View Post
Actually your service wires should go to the main breaker. Are you saying the service wires go to the lugs? A picture of your box might help. http://forum.doityourself.com/electr...your-post.html
just for my general knowledge. why would the service wires go to the main and NOT the lugs?
 
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Old 03-21-10, 04:34 PM
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Originally Posted by quickNOTCH View Post
just for my general knowledge. why would the service wires go to the main and NOT the lugs?
The main breaker protects the panel. The main breaker is there to disconnect power if there should be a panel overload or as a safety disconnect. There are other rules and exceptions that come into play in certain circumstances but that is the basics.

Main lug would be used if there were six breakers or less or if protected by another breaker in the same building. On a split panel one 240 volt breaker would usually protect all 120v breakers. There could be an additional five 240v breakers and not violate the six throw rule.
 
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Old 03-21-10, 04:39 PM
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Today's code requires you have a main breaker in the panel (this shuts off all power to the panel) and the incoming service entrance wiring would land on the main breaker. You might now have a split bus panel where the upper bus bars in the panel are energized through main lugs and then up to 6 main disconnects (breakers) were allowed on those bus bars. Those bus bars are hot ALL the time and cannot be turned off without pulling the meter. One of those six disconnects typically is the shut off for the branch circuit bus bars below where you would typically find your 15 and 20 amp branch circuits.
 
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Old 03-23-10, 08:05 AM
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let's see if this works.
 
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Old 03-23-10, 08:11 AM
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cool, at least one of them works.

well it seems as though I have other problems now. that smaller gauge wire coming from the lugs is for a sub panel that was here when we moved in about 10 years ago. the panel was unused with NO knockout knocked out. no breakers. so I assumed all was good and proceeded to wire in some circuits off it. ran a dryer circuit, and 220V for the compressor and a 15A for an outdoor light fixture. I figure the sub was in there because of the lack of room for any additional circuits in the original panel.

anyway, let's pick up from here.
 
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Old 03-23-10, 08:14 AM
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here is a second pic.
 
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Old 03-23-10, 08:19 AM
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I know that the double tapping of the lugs is against code but I never would of thought that is was wired in wrong. what can you guys tell me about the amperage now that you see pics?
 
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Old 03-23-10, 12:33 PM
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It looks to me like it's supposed to be a 100A split-bus service based on the size of the incoming conductors, but it has been illegally increased by double-tapping for the subpanel and loading tandems into the upper section. In any case, it's sort of a non-issue because the service is obsolete as I see it. The panel basically has a perfect score in the needs replacement checklist.

Overfull, double-lugged mains, double-lugged neutrals, no main breaker, water/heat damage on conductors, too many throws, unprotected sub, three-wire sub, cloth insulated feeder that I can see the aluminum shining through (don't touch that, btw).
 
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Old 03-23-10, 12:58 PM
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with that being said, do you believe THAT IT IS 100A service? in other words, from what you see, is my drop service amperage 100A??
 
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Old 03-23-10, 01:10 PM
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Originally Posted by quickNOTCH View Post
with that being said, do you believe THAT IT IS 100A service? in other words, from what you see, is my drop service amperage 100A??
Moot point really. You need to hire an electrician to change it out. He will install the proper size meter socket and the power company will determine if the drop needs up-sizing when they reconnect. Do not hire either of the two electricians who originally evaluated it. Instead get estimates from 3 licensed master electricians.
 
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Old 03-23-10, 01:48 PM
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Originally Posted by quickNOTCH View Post
with that being said, do you believe THAT IT IS 100A service? in other words, from what you see, is my drop service amperage 100A??
It seems to have started as a 100A service, but with the improper additions it is now some amount larger than 100A service based on the breakers in the upper section and the subpanel. Without a main breaker, the main conductors are not limited to 100A so they can draw current until the aluminum melts. Current is somewhat limited by the collection of all of the breakers that act as mains (upper section plus subpanel handles). This is one of the major reasons that the split-bus design is considered obsolete -- the current drawn by the service is based on a guess of typical usage amongst the various mains instead of a single main breaker. It is easy to overload the service conductors by adding breakers that were not accounted for in the original installation.

To add: In my opinion, this service is intended to be a 100A service which I think addresses your original question. In its current state it has the potential to unsafely exceed 100A.
 
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Old 03-23-10, 02:13 PM
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I talked to an electrician yesterday morning and explained the situation and he told me that it would run me in the ballpark of $1500 to upgrade. that is meter base, service panel, all other materials and labor. I'm assuming that includes permits also.

I'm just thinking out loud here guys so bear with me. if it is 100A service, wouldn't it be cheaper to just replace from the entry service wires inboard. that would be service wires and panel and breakers of course? the panel would be a 100A panel with a few more spaces so the tandem breakers could be split up.

in other words, what if I didn't want to upgrade the service but rather fix the problem of the charred wires and the lack of room for additional circuits? is it possible?
 
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Old 03-23-10, 02:33 PM
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Originally Posted by quickNOTCH View Post
what if I didn't want to upgrade the service but rather fix the problem of the charred wires and the lack of room for additional circuits? is it possible?
You're suggesting a "panel change" rather than a "service upgrade". It depends on a couple things:

You might need to replace the meter base and/or mast to comply with power company standards for reconnection; that's up to their policy which your electrician should know.

You also may need more than 100A based on demand load calculation. I don't suspect that's the case, but you or the electrician could do the math to know for sure.

The condition of your grounding electrode system. This may need to be replaced anyway so that gets you one step closer to just doing the whole service.

The issues with the subpanel need to be fixed either way, so that's also a wash in terms of added cost.

Another option is to install a 40 space 200A panel, but with a 100A main breaker. This leaves your service 100A, but allows you the flexibility to upgrade to 200A in the future if needed. The downside with this is that ordering the panel and breaker a la carte can be a lot more expensive than just buying a 200A service package that comes with everything he needs in one shot.
 
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Old 03-23-10, 03:25 PM
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It varies by location but in my area $1500 is average. Add your location to your profile and perhaps a member in your area can give a more informed comment on the average price.
 
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Old 03-23-10, 04:16 PM
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Originally Posted by ibpooks View Post
Another option is to install a 40 space 200A panel, but with a 100A main breaker. This leaves your service 100A, but allows you the flexibility to upgrade to 200A in the future if needed. The downside with this is that ordering the panel and breaker a la carte can be a lot more expensive than just buying a 200A service package that comes with everything he needs in one shot.
this option sounds like something I can live with for the time being. at least until I can make the expense to have the rest completed.

I did some research and I can pick up a 200A GE 32 circuit panel for $120 minus the main breaker. a new grounding electrode would be part of the plan, of course.

does this sound ok?
 
 

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