Odd Breaker Arangement

[John Beckman]

Greetings, I was looking at a 1955 bungalow with what is probably an updated electrical panel. However, there was no typical "main breaker" at the top, there were just two rows of breakers on each side. the stove and water heater had the typical tied breakers that would indicate that it is a 240 volt breaker. However, at the top left side of the panel there were three 100 amp breakers, side by side with their handles tied together. If it was just two tied together, I'd just say OK 100 amp service and these are the mains, BUT there were three of them. What gives, I'm thinking of buying the place and want to know what kind of elec service it has. Unfortunately I did not remove the panel cover, and I don't know the brand. Suggestions? Speculation

John

[dpb]

John Beckman wrote: ...

It would be wrong, but I'd venture the ground/neutral is the third one...

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[Nate Nagel]

or... really out there... 120V three phase? (would be 208V when two phases are connected?) How many conductors in the service entrance?

nate

[dpb]

It would be most unusual, but I suppose not impossible. I considered it, but rejected it (3P, that is) as being more likely a homeowner klutz retrofit job where lacking the one disconnect breaker of some of the cheap panels, they doofus put all three feeds onto single breakers.

But, now I think about it a little more, that wouldn't seem likely either as the third leg would have to be isolated and those boxes wouldn't have that as an option w/o modification.

My current guess is "I don't know; need more data (like a pitchur)"...

[Bob]

From your description I infer that you're dealing with 120/208 volt

3-phase service with a 100 amp main.

[RBM]

It would certainly help to have pictures, or Make and model. If it has three handles tied together, it's possible that it's a three phase service

[Don Young]

That would tend to indicate a 3 phase service, which is uncommon but not impossible in a residence. More investigation is called for, such as the number and type of conductors feeding the service and the number of transformers on the pole, if overhead service. Inspection of the panel can also tell if there are 2 or 3 main connections in addition to the neutral. The panel label should tell if it is a 3 phase panel. A three phase service would have two or three transformers and four wires from the pole and single phase would have one transformer and three wires. The meter would also say "3 Phase" or "Single Phase". If it is a single phase circuit, the triple breaker is a mystery to me unless it was used to also disconnect the neutral as is sometimes done when generators are used.

Don Young

Don Young

[Claude Hopper]

Sounds like a 3 phase setup that may or may not still be active.

[BobK207]

John-

In order to be sure....You have to pull (or have someone pull) the cover panel so you can see how its wired.

I'm thinking that someone got a "free" 3 phase panel from work (or a friend) and installed it in a residential application.

I'll bet that:

That only two poles of that three pole breaker are wired & that the installer jumpered two of the three phase buses together......such that 120V is available at every slot, but 240V is only available at certain pairings.

If it's a fairly recent Square D panel, I'd bet that the three phase bus arrangement can be changed out for a "normal" bus, they're pretty modular & can be slid in & out.

After getting a look inside the panel, I wouldn't consider this a deal breaker but you could always ask for a discount to panel for a panel rewire.

cheers Bob

[The Daring Dufas]

I've seen three phase service on some older "large" homes because they needed it for large AC units. At the time the homes were built, single phase 5 ton units didn't exist. You wrote that your example is a bungalow so I doubt it needed a lot of power. I have seen older Federal Pacific Electric breaker panels that were split, sort of like an old fuse box with heavy loads on the top and lighting on the bottom. One of the top breakers actually feeds the bottom half of the breaker box. I tend to refer to them as WTF breaker panels. Be careful of those, those panels have caused a lot of fires.

TDD

[Scott]

Looking under the cover would be the obvious next step....

If it's not 3-phase, is there maybe another breaker panel you haven't noticed? My 1960 ranch is like that...distribution panel's in the garage, but the main is outside by the meter.

[John Beckman]

Bob, We have a winner. I got back out to the house today and took a closer look. The overhead from the power pole had two insulated conductors and the bare ground wire. I took the cover off of the breaker box and the two hots were hooked up to the top two of the triple 100 amp breakers. The third breaker had a jumper from the second 100 amp breaker. So it looks like I have a three phase box rigged to give me standard residential service. Like you said, not a deal breaker but since I'll be upgrading from propane to a heat pump, I'll upgrade the electric service then.

Thanks all John

[Nate Nagel]

Were the breakers jumpered on the line side or the load side? I hope load. Should be fairly easy and not too inexpensive to just buy a proper new box and swap it out (even without upgrading service.)

That does of course prompt the question - if the last guy was too cheap to pop a buck fifty for an appropriate breaker box and/or didn't know that his trash find was wrong, what else in there ain't right? Not saying you can't find a nice place with something like this going on, but just take a critical look at other "improvements."

nate

[hallerb]

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get a home inspection and drop price you pay, based on home troubles and non code issues

[BobK207]

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John-

Thanks for the followup. Yeah, not a deal breaker but to "fix it right" will take a new panel or a new bus within the panel and some time.

It's way too weird for a "regular" homeowner so I would recommend asking for some $ to "make it right". imo ~$1000 for PITA, etc

btw the reason I was guessing that this was the case.........

I had a friend who did the same thing....install a 3 phase panel in a residential subpanel situation. I told him it was more than a little "non-standard" but he figured the price was right & he'd be long dead before anyone figured it out. And in his opinion it wasn't a safety issue. IMO is going to be a little bit of a brain teaser for someone in about 20 years. It's a Square QO so at least the hardware is good.

He paid $100 for two 3 phase sub panels with about 30 single pole breakers & 10 240 volt breakers......just for the cost of the breakers he figured the panels were free. The panel has no "main" so it the "mis-application" is going to be undectable until someone installs a 240V breaker across the "common hots".........not voltage.

cheers Bob

cheers Bob

[Tekkie®]

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te:

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Then hollerbutt will be over to short any two wires of your choice together= to=20 pop the breaker (he calls it *testing*) or blow something up.

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