Basic electrician question

Usually I can figure this stuff out myself, but I don't see the answer here and never had occasion to do it before.

In the electric box that feeds my house, I want to replace one circuit breaker. What holds them in?

I think my box is pretty standard. There are busses for the two legs of

220 down the middle and some kind of clamp strips down the outsides that holds the CBs.

Hope that is enough info for an answer.

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Kind of a tight fit on most, but the outer (wire connection) side of the breaker usually has a little space in it for a metal leg to slide into, then the breaker is rotated in toward the center of the box and pressed into place. To remove, the end of the breaker close to the center of the box will have to be pulled out toward you a bit to get it loose from the buss bar, then can be "un-hooked" from the metal tab on the other end. HTH Ken.

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Ken Sterling

I've got a squareD and cutler hameer that both work the same. Don't know anything about other boxes...

The breaker just snaps in place. Kinda rotates around the outside round bar clip. THe inside clip pushes into the electrical bus last or pry it out here first. DISCONNECT THE TOP MAIN FIRST.

Maybe get your replacement so you can see it first.


Reply to
Karl Townsend

SOME boxes in older homes use "Pushmatic" breakers. These are held in with a screw. And the screw is, as I recall, hot. So, regardless of the type of breaker, turn off the main before you try removing it.

Reply to
Jerry Foster

There are two types of breakers - Snap in and screw in. Most residential breakers are push in without the holding screw/

Both types come out by pulling out on the outside edge of the breaker. The very best thing would be to go to Home Depot or some such and actually push one in and out on a new, fresh. DEAD panel.

(top posted for your convenience) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing . . . . DanG (remove the sevens)

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Spring pressure. Turn breaker off. Remove wire after loosening clamp screw. Pull breaker out from the middle of box, where the two rows almost touch. The outer edge of the breakers hook onto an edge and hinge from there.


Reply to
Jon Elson

Tell us the brand of the panel and the models of the breakers, and we can easily answer the question. Or stick a picture up somewhere.

Most modern breakers plug straight onto the two rows of buss stabs in the middle of the panel, and they have hooks on the outboard side to keep them in the panel. Cutler Hammer CH and "Challenger" or "Bryant" BR, Crouse Hinds/ Murray/ Siemens MP QP, GE THQP THQL, SquareD Homeline, etc.

The hooks are 'coded' in some panels, and the buss stabs notched to reject double breakers in a large 42-breaker panel. And some brands have other odd rejection methods, like the pins in the back of some FPE panels that fit in holes in the back of the right breakers, and all their odd buss stab plug patterns.

Square D "QO" has two spring clips, one for the hot buss, one for the locating rail. Except for some of the old QOT tandem breakers that use a metal hook for the locating rail, restricting them from being used in certain Non-CTL panels. (Keeps you from going over 42 poles in a panel.)

Same two-clip design with the antique SquareD and Cutler-Hammer XO design breakers - if you have an XO panel, plan to change it. You are NOT going to find replacement breakers for anything approaching a reasonable price, and they're going to be used take-outs.

True, though bolt-on breakers other than ITE Pushmatic are usually found in industrial panels. It's legal if they have 'walked home from the plant' and been installed in houses, but finding replacement breakers is a supply-house-only pain in the ass. You usually find a B in the part number as a good clue.

If you have nerves of steel you can change bolt-on breakers with the panel hot - though you need to take proper precautions like using insulated tools, cardboard or plastic to isolate open hot stuff that can be blocked off, and a screw-grabber screwdriver to avoid dropping the screw into hot areas - they're JUST long enough to cause shorts if they land in the wrong place.

And you can /not/ trust any screw retaining washers or devices used on bolt-on breaker line tabs 100%, they sometimes don't retain the screw when called on, with potentially disastrous results. You usually see the thin retainer tab under the screw on original Pushmatics.

In other words, if you don't do this stuff every day, take the safe route and turn power off to the panel before poking around inside - and get a Wiggy so you can be assured it's really dead.

I even turn stuff off if I think something is seriously wrong inside

- like the supports are broken or burned, and hot parts might spring together and short out when I take the breaker out.

Discretion in electrical work is the better part of being able to count to 10 without taking off a shoe. (Or counting stumps.)


Reply to
Bruce L. Bergman

Back in the '50s, Pardee Homes built tract houses that used Pushmatics in the original construction. And they didn't have a main cutoff! The only way to kill the panel power was to pull the meter head. (I used to own such a house in San Diego...) And a friend in San Jose had a house with Pushmatics, but that looked like a re-wire job from probably 40 years ago. I assume they are fairly common in these areas because the local hardware stores carry replacement breakers.


Reply to
Jerry Foster

Thanks to everyone for the replies.

Once I understood that they pull out on the bus bar side, I easily got it out. Went to Home Depot and discovered that I needed a type-F but they didn't seem to have any. Orchard supply did have what I needed.

Yikes! A 2-pole 50A breaker costs about twice what I would have guessed.

So with the advice gained here I got my project under control.

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Type F, as in Federal Pacific or Federal Pioneer panel? If so, your work may just be beginning. Apparently, the Federal breakers will not reliably trip on overload. Don't know about replacements manufacturered by other companies. You might want to do a search of the internet with keywords "Federal Pacific breaker" or something similar.

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New ones are apparently OK - it is just after years of use they degrade. From what my dad, a retired "sparky" says, anyway.

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There were several varieties of no-Main panels built, including the Zinsco "Crowfoot" panel, so named for the odd main busses that looked like two crows feet branching from the meter socket to the three breakers on that side. And they need the Q breakers with a screw input tab on the LINE side, no new ones are being made.

The trick is that by NEC Codes you are limited to six fuses or breaker poles without a main disconnect in the panel. And the Crowfoot design got you only one true 240V common-trip breaker in the middle. The only legal way to add extra circuits is a sub-panel.

These panels are great for billboards or guard houses, but six poles will be full in no time flat in anything bigger than Ted "UnaBomber" Kaczynski's one-room tarpaper shack in the woods....

But try telling that to someone who stuck another breaker in the blank spot at each end of the panel and rigged wire jumpers to the LINE side crowfeet to heat them up.


Reply to
Bruce L. Bergman

my house was built in '47, in southern CA - it was a cheap house at the time, I presume. when I bought it, it had the original breaker panel - that panel had two breaker assemblies, each contained a single 15 and a single 20 amp breaker with one input (screw terminal) and two output terminals - that was it - In 47, I suppose they didn't use much juice? anyway, one day the

20 amp side of one of them started to trip at about 6 amps (e.g. when I turned on my microwave), so I pulled it out (there was no main breaker, and you couldn't pull the meter either, it wasn't in a socket and still isn't) - I knew I was in trouble when I took the thing to the local good hardware store and they looked at it and said "what's that?". I believe my house was typical of those in this area, although I may be the only homeowner who here who does his own wiring work today.


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Type F? As in FPE - Federal Pacific Electric / Federal Pioneer Electric (Canada)? If that's the panel you have in the house, change out the main service or panel as soon as possible. There is a large body of evidence leading to the conclusion that continued use is not safe. In my opinion, I would call circuit breakers that can jam into a condition where they will not trip under any level of short-circuit overload "a big problem".

I am serious, this isn't an "emergency" but should be done when you can. Call your local power utility for a 'meter spotting' to see if they want you to move the service entrance or go underground, make your plans (Okay, pencil sketches), pull the permit if you need one, and get the materials together for a panel change. Wait for the weather to be nice, pick a day, and do it.

Don't take my word for it - go do some Googling around on it, but start at

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Nobody is willing or able to force a recall - since the original company went bust, and the CPSC got their ass handed to them by Alcoa over aluminum house wiring so they didn't want another drubbing. And American Breaker who makes replacement FPE breakers of course is discounting all the talk about problems as baseless... But the basic conclusion remains: IMHO FPE panels are junk that needs to be pulled from service, especially at the first signs of trouble.

And there must be something behind it, there are some property insurance companies making panel replacement a condition of issuing insurance, they're having to rip out panels 50 at a time at condos.

There is some evidence that Federal Pacific faked their UL Rating testing for the breaker trips and general durability for service, and the entire line has been delisted. (But what Reliance Electric found about that is in sealed court records.) The breakers show a nasty habit of failing to trip on overload or jamming to where they can never trip, and the panel and busbar designs are a stinker - the panels meltdown in a failure. On some panel designs they run 200 Amps from the Main through an 8-32 screw to the main buss.

Whenever I hear multiple credible reports of stuff like this, I worry. You should NEVER have a breaker fail to trip on an overload of

200% or more, or on a bolted fault short. But this appears to happen to a large sample of FPE breakers found in use in the field.

The generic Korean replacement breakers sold in the hardware store are even worse - the retail stores should be held liable for selling equipment in the US that is not UL-listed, but the management must feel that Ignorance Is Bliss.


Reply to
Bruce L. Bergman

This is a point of contention in the industry. All the replacement breakers I've seen (both the American Breaker "OEM" replacements and the Taiwan copies) are duplicated mold and tooling knock-offs of the original, not redesigned to increase the reliability even though they have reason to know there is a problem.

I suspect that if you put the brand-new parts through the same testing, they would be failing at the same rates - I would do it myself but I don't have the testing equipment.

Bad design is bad design, making new 'duplicate' copies of a bad design does not make it any better. If anything, copies made by people who don't understand how minute changes in materials, sloppy tolerances or wear on the tooling affects the end product can make them even worse.

And the Taiwan folks can churn out the junk and sleep at night knowing they can't be sued for product liability because the laws are lax to non-existent, no matter how faulty the product...


Reply to
Bruce L. Bergman


Yes, this is exactly the stuff that is in my house.

For a while I have been thinking about getting better input current rating, but I think this will be a major pain because the input wires run through a conduit under a slab poured for my living room. To make this bad situation worse, the input feed wires are aluminum.

Geez, what a pleasure to learn that the whole electrical system in my house (other than the copper wires to the outlets) is crap.

I already know I must have a new roof this year. Now I learn I really should consider complete new electrics too.

How delightful. But thanks for enlightening me on the subject. Guess I should pass the basics of this information on to my neighbors. We all must be living in a realm of danger.

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Aluminum INPUT wires are not a big problem, they are quite common. Just use the special non corroding grease when installing and crank the bolts down to the specified torque. If you want to change these to copper, the copper wire is one size smaller so you can sometimes get an upgrade in capacity through the same conduit.

Aluminum wiring to the outlets is the BIG problem, several cures, best is full remove and replace.

But it does sound like a new service panel and/or service entrance is > >

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Builders liked FPE equipment - it was really cheap to buy, and every buck they can save adds to the profit... Good for them, bad for you.

That you can't get away from - those wires belong to the power utility, they supply and maintain them, and are responsible when they go bad. You only own the conduit from the house to the property line, pullbox at the street, or the base of the pole.

The utility can pull larger wires through the existing conduit if you want to upgrade the panel, no need to tear up the house slab. You're supposed to use 2" conduit for 200A feed wire, but they might let you use 1-1/2 if that's what is there - call them and ask. But if you want to bump it to a 400A, that's going to take a bigger conduit.

(They usually cheat, using smaller wire than you have to, because they're the utility and they can... You land 3/0 CU THHN for 200A output, they use 2/0 AL XLPE XHHW and reduced neutral to the pole.)

And inside the house, AL wire is still legal for single-point runs like to the air conditioner, water heater, range outlet, sub-panel main feed, etc. The breaker and the load lug at the other end (disconnect switch or receptacle) must meet the new CO-ALR ratings, and the wires must be properly cleaned and coated with NOALOX compound at both ends.

I won't install AL wire myself inside a house unless the customer is informed and still insists because of price (It's their house...), and outside "Bronco Wire" AL aerial drop wire runs to outbuildings only because that's all you can buy.

What, you want I should blow smoke up your ass, tell you it's all a bed of roses, and leave you fat dumb and happy - until something goes seriously wrong?

Knowledge is power, and I'm not afraid to share.

The only thing I have to do is be careful to use lots of 'wiggle words' like "In My Opinion" because the breakers and panels are not all bad, there's no rock-hard proof to say something like that, and there are still corporations involved (selling replacement breakers) with a large financial vested interest in this not becoming a panic situation or a huge recall.

( Can you say 'Lawsuit'? Knew you could.)

The important thing is to get the panels out of service as they age and deteriorate. Hopefully catching them before they self-destruct.

It's not an imminent danger, do not panic - but if you or the neighbors have a FPE panel you do have to be aware that there is a problem. And get any odd electrical happenings like dimming lights, humming or buzzing sounds (wires vibrating in the walls at 60HZ from a large overload), unusual appliance operation, odd toasty burnt bakelite or tar smells... checked out ASAP.

And when the local electrician says "It's Fine..." have him take out the breakers, pop out the main buss and /really/ check it over, front and back - the stuff that 'goes melty' is buried deep inside.

Buy yourself an Infrared Non-Contact Thermometer, they're down to below $100 and a very handy tool to have around - I love mine for confirming suspicions. If the house is 68F, and a monitoring scan finds that most of the panel guts are around 75F - 80F but there's a hot spot inside the panel or on a breaker coming up at 275F, you found a problem.

The metallic breaker box /should/ keep any fires inside the box and not allow it to spread, but there are no absolute guarantees in life. The piece of equipment at the other end might go , but UL design rules apply there too.

If your roof is really that bad, it has to get done first (and while the weather is nice) and the panel can wait a while. You can't put on a new roof in the middle of a storm, but the panel is inside or can be sheltered.

But I'd strongly suggest that you do all the planning and pre-prep for the panel change, and get all the stuff you need bought and in a neat pile in the basement. You have time to order in the panel you really want. You can even upgrade the bedroom circuits to Arc-Fault breakers to meet the latest codes, AFCI's aren't available for discontinued panels.

The equipment is only a few hundred bucks, even with all new breakers - and if the old panel goes bad you are ready to go -now-.


Reply to
Bruce L. Bergman

A Vietnamese friend of mine asked me to come over and check out a problem that he had with the wiring in his house. (I carried a California C7-C10 for 16 yrs). Half the house was dead. I found all the wiring in the house was aluminum. BRRRRRRR! At this point I knew he was in trouble and recommended a current residential electrician. Some hours later the electrician found an outdoors outlet had all the wiring in it burned away, causing the 60's vintage house (4 breakers) to loose power in the damnedest places. Split level, flat roof, on a slab. No crawl space, no attic. I think he is going after the real estate agent.....


"Considering the events of recent years, the world has a long way to go to regain its credibility and reputation with the US." unknown

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I lived in a house that had aluminum wiring and I too had a problem with wires burned at a outlet. Scared the hell out of me. I then went around looking at every outlet, switch and ceiling light I could find and tightened the screws. Some of them were very loose. Glad when I moved out.


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