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Tool to remove circuit breaker nut?

Saville

Well Known Member
Hi all,

I have to remove a row of circuit breakers to re-wire one.

They are fairly close together. I need to remove the thin flat nut that is used to secure the breaker to the panel. Is there a special tool that makes loosening the nut easier. I tried a wrench. It got the nut off but not.....gracefully. They are klixons, I believe.

I suspect there's a good way to do this. I will try a hex socket but I don't know if I can get the wall of the socket between the breakers - although they had to be tightened somehow in the first place.

Any ideas welcome.

Thanks!
 
Several options here. I have had to modify a 1/4 inch deep well socket for some of the planes I have worked on. Just grind down the outside perimeter of the socket to get it over the nut and between the adjacent CB nuts.

Another option is to use an open-end wrench, but held perpendicular to the panel. This allows you to turn the nut about 1/6 of a turn before you have to reposition the wrench.

The last option is to start at one end of the row of CBs and remove the nuts and washers from each and every one until you get the the one you are after.

These gyrations are caused by builders who brick wall the CBs and don't leave room between the items to easily maintain them.
 
Why is it whenever I see posts like this my brain always yells "bench grinder!" :D

As-in, take a cheap-o (or not) spare socket and apply 1/8" or so of the end to a grinder wheel while rotating until you've made enough sparks to have a socket that will fit between the breakers.

There's another thread about made and modified tools, this could go there.
 
Several options here. I have had to modify a 1/4 inch deep well socket for some of the planes I have worked on. Just grind down the outside perimeter of the socket to get it over the nut and between the adjacent CB nuts.

Another option is to use an open-end wrench, but held perpendicular to the panel. This allows you to turn the nut about 1/6 of a turn before you have to reposition the wrench.

The last option is to start at one end of the row of CBs and remove the nuts and washers from each and every one until you get the the one you are after.

These gyrations are caused by builders who brick wall the CBs and don't leave room between the items to easily maintain them.


Thanks for the ideas. So there isn't a special tool or technique. It's just grin and bear it.


I got the one nut off by the 1/6th turn open end wrench method.

These breakers are on the right hand side of an RV-8 panel - the part that's riveted to the plane. So there's no simple way to get at the connections in the back. "bricked: is the word.

When I got the one nut off the 3rd breaker in a row of 4, I tried pushing it into the panel to see if it would move...rock solid.

I'm hoping that it doesn't move because of the bus bar that connects it to the other 4. That's why I think I need to remove the nuts from the entire row.

But if there's some other reason.....
 
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Why is it whenever I see posts like this my brain always yells "bench grinder!" :D

As-in, take a cheap-o (or not) spare socket and apply 1/8" or so of the end to a grinder wheel while rotating until you've made enough sparks to have a socket that will fit between the breakers.

There's another thread about made and modified tools, this could go there.

Thanks for the idea Randall
 
Breaker Removal

Always a great idea to disconnect the battery before a job like this. Good suggestions listed above. I like to polish the end of the socket that will contact the panel glass smooth. You can also put a balloon or packing tape over the end of the socket to protect the panel.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
 
Ok the socket worked and the row of 4 CB's pushed out of the panel. Was extremely difficult getting 2 ring terminals on the CB but I managed to do it.

Thanks everyone for the suggestions.
 
As a rule I try to place Klixon breakers 3/4" apart. You can buy plated copper bus bars with holes already drilled in them at 3/4" spacing. Mil Spec part number MS25226. So if you make your panel holes at exactly 3/4" horizontal spacing the bus bar will match perfectly with the breaker contact screws.

51a8IyuZb0L.jpg


Sometimes I have the breaker holes laser cut in the new panel with the rectangular indexing nibs inside the holes to match the slot on the breaker barrel. On smaller projects I manually drill the breaker holes with a 7/16" drill bit and then add 1/8" holes in the instrument panel above each circuit breaker hole so the breaker's indexing washer can engage this hole from behind keeping the breaker locked in place to resist rotating when tightening. Here is a recent layout I did for a Super Cub wing root breaker/switch panel:

BygKc3e.jpg


I printed that out on adhesive label paper at 1:1 scale and stuck it to a piece of aluminum to fabricate the panel. Spring-loaded punched the cross hair center marks for drilling. Corner extension lines help line up the metal shear blade cut. The 3/4" horizontal spacing is about perfect for Klixon and P&B breakers and future maintenance is enhanced.

When it comes time to change one out, I remove ALL nuts on all breakers in the line and push the whole assembly with bus bar and wires attached through the mounting holes so that the entire bus bar/breaker cluster drops down and is accessible for the work. After replacing the breaker in question with the bus bar and load wire re-installed, it is a simple matter to insert the whole line of breakers back into the line of holes and re-attach the nuts with star washers. I like to use a deep well socket and sometimes put masking tape over the end of the socket and cut out the hole so the socket won't mar the panel when tightening.
 
As a rule I try to place Klixon breakers 3/4" apart. You can buy plated copper bus bars with holes already drilled in them at 3/4" spacing. Mil Spec part number MS25226. So if you make your panel holes at exactly 3/4" horizontal spacing the bus bar will match perfectly with the breaker contact screws.

51a8IyuZb0L.jpg


Sometimes I have the breaker holes laser cut in the new panel with the rectangular indexing nibs inside the holes to match the slot on the breaker barrel. On smaller projects I manually drill the breaker holes with a 7/16" drill bit and then add 1/8" holes in the instrument panel above each circuit breaker hole so the breaker's indexing washer can engage this hole from behind keeping the breaker locked in place to resist rotating when tightening. Here is a recent layout I did for a Super Cub wing root breaker/switch panel:

BygKc3e.jpg


I printed that out on adhesive label paper at 1:1 scale and stuck it to a piece of aluminum to fabricate the panel. Spring-loaded punched the cross hair center marks for drilling. Corner extension lines help line up the metal shear blade cut. The 3/4" horizontal spacing is about perfect for Klixon and P&B breakers and future maintenance is enhanced.

When it comes time to change one out, I remove ALL nuts on all breakers in the line and push the whole assembly with bus bar and wires attached through the mounting holes so that the entire bus bar/breaker cluster drops down and is accessible for the work. After replacing the breaker in question with the bus bar and load wire re-installed, it is a simple matter to insert the whole line of breakers back into the line of holes and re-attach the nuts with star washers. I like to use a deep well socket and sometimes put masking tape over the end of the socket and cut out the hole so the socket won't mar the panel when tightening.


jliltd,

All good ideas. When I re-do the panel on the plane - and the rat's nest wiring behind the panel, I'll use some of your ideas. I will also put the breakers in a location that allows me to get at the connections without having to crawl under the panel.

This was torture. Trying to get two ring terminals on one breaker where you had to be under the instrument panel, around the stick with a head lamp, working through a nest of wires, where you couldn't hold the screw to the breaker with one hand and work the screw driver with the other - you had to push with the screw driver against the flexing of the wire and hope that you could get the screw started without a ring terminal coming off....was awful and I hope I never have to do that again.

Thanks
 
Screw starters are handy for tasks like this

Possibly. One of the problems I had was that the second ring terminal would fall off the end of the screw before I could get the screw aimed at the CB.. Not sure how a screw starter is going to help there.

But I'll look into it.

Thanks
 
Options:
1. Re crimp the two wires into one single crimp ring terminal.

2. Position the ring terminal closest to the CB tab, form the wire to have it want to lay in a position so that the exposed ring terminal just lines up with the exposed threaded tab. Now, insert the screw through the second ring terminal and carefully guide it through the first ring terminal and into the CB tab.

3. When using two ring terminals, position the one closest to the CB upside down. Then the last one right side up. This just helps to nest the terminals together.

Don't forget to use the split lock washer next to the screw head.

The screws that come with the CB are 6-32. They will just "fit" with two ring terminals and the lock washer attached, and it also depends on the thickness of the metal ring terminal material. It may be a good idea to have some slightly longer screws on hand. I always pre fit ring terminals to a CB to check the screw length required. If the screw is too long, it will contact the plastic body of the CB and either crack it or make you think the screw is tight when it isn't.

If you need a "screw starter" to hold the screw onto the tool, you can use some tape to hold the screw and lock washer to the screwdriver. Once the screw starts to engage the threads of the CB with the captured ring terminal(s), remove the tape and finished torquing down the screw.
 
Options:
1. Re crimp the two wires into one single crimp ring terminal.


I considered this but didn't know the sizes I should choose:

One wire was AWG 22; the other wire was 16.

Would I use one blue ring terminal for combining those two?

Thanks
 
Split lock washers are not really lock washers. Nord Lock did vibration testing of
various lock washers. Split ring washers actually cause a fastener to loosen
quicker than no washer at all. I do not think that split ring washers are used on
cars. They should not be used on airplanes.
 
This was torture. Trying to get two ring terminals on one breaker where you had to be under the instrument panel, around the stick with a head lamp, working through a nest of wires, where you couldn't hold the screw to the breaker with one hand and work the screw driver with the other - you had to push with the screw driver against the flexing of the wire and hope that you could get the screw started without a ring terminal coming off....was awful and I hope I never have to do that again.

Thanks
HAHAHA, Now you know why those of us that no longer fit under an instrument panel will pay for somebody to do this work even though we can do it our self.

:(
 
Maybe replace your circuit breaker mounting panel with one similar to the one on sold by Steinair. Its mounted with screws, easily accessed & easy to maintain.
 
One wire was AWG 22; the other wire was 16.

That is quite a size difference. What is the rating on the CB? You might want to do a load calculation on those two circuits and see if the #22 wire is protected.
 
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