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Two service equipment


Chad Fabry
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Tell me what they were thinking please:

4/0 aluminum se cable, fed from the meter to a gutter where three "kearney" split bolt connectors were used to tap three 4/0 aluminum off to a 100 amp throw cartridge fused main which feeds a 100 amp sub upstairs, while the run of the original se cable feeds a 200 amp panel.

1) doesn't this have the distinct possibility of drawing 300 amps?

2) what would be the point of using this method over feeding the upstairs sub from a breaker in the nice 42 circuit panel that's been there (previously a 42 circuit bulldog pushmatic...I have it) since day 1?

photo 1 is the gutter and the splice.

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Photo 2 is the panel which would normally be the only service equipment.

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Photo 3 is service equipment part two?

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Photo 4 is the whole shootin match

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1) doesn't this have the distinct possibility of drawing 300 amps?

Well, the sec does not have the correct over-current protection.

2) what would be the point of using this method over feeding the upstairs sub from a breaker in the nice 42 circuit panel that's been there since day 1?

When I have come across similar installations, the "upstairs" was at one time an apartment, or in-law suite that had a separately metered sec feeding the smaller service equipment.

Typical old farm distribution system. At least these are usually all after the main fuses/disconnect.

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The whole thing is odd and to further confuse matters there was yet another (stab lok) panel down stream from the cartridge fuse "service". The Federal Pacific equipment was wired with just the two hots and a neutral. Ironically the whole thing was just reviewed by an electrician who installed the nice new panel with all the breakers the day these photos were taken.

The apartment idea may be a factor; there was some abandoned plumbing on the second floor.

The thing is, it doesn't do any good to separate the service after the meter.

They may have tapped off the service entry cables in anticipation of separating the upstairs from the down stairs and installing another meter at another time?

It doesn't feel that right to me because it was a nice, yet modest home that didn't lend itself well to a duplex future.

You all know that I'm not a code guy, I've never quoted code and my eyes glaze over when most people do. I've always been an "understand how it works and use common sense guy".

NEC 230.2 is where I think I should be looking and to issues with bonding.

Kurt Mitenbuler and Bill Kibbel are two of the friggin gurus I encourage folks to emulate (except for Kurt's slightly sardonic demeanor)

I'd still like to hear from Jim Katen

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Originally posted by Chad Fabry

1) doesn't this have the distinct possibility of drawing 300 amps?

Well, not really. Bill's right about the SEC, but most of the time an average 200 amp service isn't actually carrying more than half of that (usually far, far less). My first thought is that it isn't really any more likely to draw 300 amps than it would be if the whole thing ran to the 200 amp panel first, it just has greater disaster potential if it ever did. I'd have to call it, no question, but if it were in my house I wouldn't be very concerned. Maybe I'm up too late. [:-sleep]

2) what would be the point of using this method over feeding the upstairs sub from a breaker in the nice 42 circuit panel that's been there (previously a 42 circuit bulldog pushmatic...I have it) since day 1?

Unless it's something like what was already suggested, beats me. I'd have done it the same way you would.

Love Bill's photo. [:-crazy]

Brian G.

Some Electricians Don't Need a Reason [:-dog]

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Orginally posted by Brian:Well, not really. Bill's right about the SEC, but most of the time an average 200 amp service isn't actually carrying more than half of that (usually far, far less). My first thought is that it isn't really any more likely to draw 300 amps than it would be if the whole thing ran to the 200 amp panel first, it just has greater disaster potential if it ever did. I'd have to call it, no question, but if it were in my house I wouldn't be very concerned. Maybe I'm up too late.

Hi Brian, nice to see you.

I realize that there's almost zero likelihood of actually having a 300 amp load.

If you or anyone else could help me understand if there's bonding issues, I'd appreciate that.

One side of my brain says "what's the difference" but the other , darker side keeps nagging that there could be step potential problems.

Of course I would suggest that the house be wired along more conventional lines. Just the same I'd like to better understand the issues.

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Sorry for not chiming in sooner. But I'm as puzzled as you are.

Originally posted by Chad Fabry

Tell me what they were thinking please:

4/0 aluminum se cable, fed from the meter to a gutter where three "kearney" split bolt connectors were used to tap three 4/0 aluminum off to a 100 amp throw cartridge fused main which feeds a 100 amp sub upstairs, while the run of the original se cable feeds a 200 amp panel.

1) doesn't this have the distinct possibility of drawing 300 amps?

Only if there's 300 amps worth of load attached to it. This is exceedingly unlikely in a modestly sized house. In fact, it'd probably never pull 200 amps either.

2) what would be the point of using this method over feeding the upstairs sub from a breaker in the nice 42 circuit panel that's been there (previously a 42 circuit bulldog pushmatic...I have it) since day 1?

I don't know the answer. Speculation follows:

  • The previous bulldog panel wasn't original. Perhaps it was a replacement. Those were popular panels at least through the 70s. How old was the house? Could it have had a 100 amp service, then someone upgraded the meter can, installed 4-0 wire and added the second disconnect? Then later, someone added the Bulldog?

If it was like this from day one, perhaps the explanation is as simple as the electrician wanted to cheat. That was one of the chief appeals of the old split bus panels -- you could overload them without tripping that pesky main breaker.

It was to be a seperately metered feed to a rental unit. This seems unlikely because I'd expect to see a provision for a meter.

From the pictures, the bonding looks ok. The FPE panel outside the picture probably needs a fourth grounding wire in the feed, but that's pretty much a given in a house this age. Nothing special there.

One other thought. You could always call up John M. Celmer and ask him.

- Jim Katen, Oregon

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