Utility wiring question

Greetings. My wife and I purchased our home a little over a year ago. The inspector didn't see anything unusual. Now that I've had time to do some bumping around and some minor improvements, I've discovered what I think may be an odd situation.

I'll diagram the wiring below. The home has 100A service off of a pole. It used to come in through the service entrance to our main panel in the basement. Circuits are taken off of both legs and everything is happy.

The previous owners added an outdoor hot tub. To facilitate this, they had an electrician add a "sub panel" in line outside. They then added a circuit for the hot tub. When we purchased the house, we didn't want to keep the hot tub, so they moved it out for us.

Logically, now, wouldn't the inside old main panel be considered a sub panel because it is fed from a breaker in the new box outside? Here is where my concern is. Since our main (inside) panel is coming from a 100A breaker in the outside box, our whole house is now drawing all from jsut the left leg of our service. The right leg is completely empty. The diagram should help:

UTILITY POWER H H N H H N H H N METER-BOX H H N H H N H H N ------------- |outdoor box| |added on | New outside box added on to service hot tub ggg| H H N | g | H H N | g | H H N | g | H H N | 100A breaker feeds inside panel from left leg g | 100A H N | g | h h n | Right leg is empty g ------------- (I have since added a 15A GFCI breaker for g h h n outdoor pond pump and lights) g h h n g h h n g h h n g h h n g ------------- g |indoor | g |master box | Original inside breaker box g |full of | ggg|circuits | Now fed only from left leg breaker in upper box g | h h n | g | h h n | g | h h n | g | | g ------------- g EARTH

Is uneven leg load a problem? This is an odd setup? It was installed by an electrician, not a DIY job. I like having the outside panel, it allows easy landscap wiring and such. But if an uneven leg load is a problem, something will have to change. Is there a breaker that will span both legs to feed the inside box with power from both legs, but still break when needed?

Thanks to all of you with the patience to get this far.

Chris

Reply to
Chris
Loading thread data ...

I do not understand fully the issue your trying to explain. Pictures? or call the local electrical inspector.

Reply to
SQLit

Sorry, but I couldn't make any sense out of your diagram.

Are you saying one hot goes to your house and the other goes to an outside panel? That would be a very bad thing if it is true.

Do you have anything using 240v in your house? A A/C, a stove, a dryer? If so, then you are mistaken; you must have both legs going to your house. If not, then I still think you are mistaken; no reason except that no one would ever wire a house that way.

Reply to
toller

In article , Chris wrote: [snip]

If it's a double-pole breaker, then the house is being fed from both legs.

Breaker boxes are constructed such that alternate breakers are on alternate legs, not (as you seem to believe) with all the breakers on the left side on one leg, and all the breakers on the right side on the other leg.

Go to a hardware store or home center, and look at the breaker boxes on display there, and you'll see what I mean.

Reply to
Doug Miller

Chris What is not obvious to you is that the raised contacts that allow the breaker to pick up power from the buss bars are alternated between the two buss bars. The breaker that feeds your interior panel is two pole and each pole has its own pick up clip. Since two contacts set beside each other are on separate buss bars one pole of the breaker is on the left buss bar and one is on the right buss bar.

What brand and model number is the outdoor panel? I ask because some can be fitted with an interlock kit to permit the supply for the house to be safely switched to a portable or mobile engine alternator set (generator).

-- Tom H

Reply to
HorneTD

If the 220V electric stove or dryer in your house works then your house panel is being fed from both "legs" of the outside panel.

Reply to
HotRod

Thanks for the tip on what to look for. This is a GE panel and I only noticed the two legs bolted to the two buss bars up at the top. Taking a minute to see how the busses are combed together makes a lot more sense. Since this panel only has two breakers in it, it was very easy to see. Our other panel is just about full and you can't see the buss bar layout beneath the breakers.

I really appreciate everyone's help. I have to ask questions to learn. Which reminds me, is there a difference between the hot legs coming in? Are they 180 degrees out of phase? So, is resedential power two-phase? I read about these big three-phase motors for commercial equipment over at the rec.woodworking group and how they won't work in resedential without a device to "generate" the third phase for the machine to properly work.

-- Chris

Reply to
Chris

I believe the technical term for residential wiring is "split-phase." There is a single phase fed to a center-tapped transformer. The two hot leads are the two ends of the secondary coil and the neutral is the center tap. This effectively gives you 120V on each of the two leads with respect to the center-tap, and since they are 180 degrees out of phase with each other you get 240V across the two hots. The neutral is bonded to a ground at the service entrance or main breaker box and the neutral and ground should be kept separate from there on. You can think of residential power as 2 phase, but that is technically incorrect. 3 phase has 3 hot leads that are

120 degrees out of phase with each other. Depending on the service you can get 120V out of each phase to neutral, but the phase-to-phase voltage is 208 instead of 240 because of the phase angle not being exactly opposite. You almost never see 3 phase in residential, certainly not in single family, situations. I have seen it in an apartment building, but only up to the service entrance. No apartment got all 3 phases.

Bill Ranck Blacksburg, Va.

Reply to
ranck

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.