Advise on 60's Murray 100A panel

[jeremymc7]

Looking for a few things here.

As you can see in the photos I have an OLD (late 60's) Murray 100A 240V breaker panel. I don't think there are any current / new breakers that work here, right? And I'm not ready to do panel swap 200A upgrade yet at this point.

I have a wide 20A 120V (upper left) that I want to replace with a double slim to give me an extra slot. Box is full.

II also need to put in a double slim 30A 240V breaker for a dryer outlet with wires run but disconnected at outlet and panel to the disconnected Nema 10-30.

There also look to be a breaker or two (see upper right for example) that are not Murray EP and also while not the recommended type has been put in and "function" but as you might seem are not "fully" snapped in and might be a good idea to replacing even though they've been there for 15+ yrs.

FYI there is no dedicated ground wire in the house. But there are metal boxes and conduit.

Also all the wiring is 12 gauge 20A solid copper which likely why most of the breakers are 20A instead of 15A - even though most outlets are 15A in the house. Not sure if that's problem running 20A breakers, with 20A wire through 15A outlets. Maybe the outlets should just all be switched to 20A or replace all the 20A breakers with 15A?

So recommendations here.

1. Can I still compatible breakers here instead of used / refurbished 50 year Murray ones? Murray itself is obviously long gone.
2. What other breakers should I replace and why?
3. Other cost effective options I'm missing here?

 

[qdeathstar]

There are no photos. Murray breakers are still for sale, but maybe not for your panel, if they are pushmatic breakers, for instance.

Outlets don't need be replaced with 20 amp outlets unless they are dedicated.

My suggestion is to replace the 100 amp box with a larger (more space) box. You can get a 24 space panel and the cost to install it will be much less then than the cost to upgrade, most likely.

 

[jeremymc7]

There are no photos. Murray breakers are still for sale, but maybe not for your panel, if they are pushmatic breakers, for instance.

Outlets don't need be replaced with 20 amp outlets unless they are dedicated.

My suggestion is to replace the 100 amp box with a larger (more space) box. You can get a 24 space panel and the cost to install it will be much less then than the cost to upgrade, most likely.

Check again I added the photos in a resave and they're up there.

I figure pulling the upgraded panel, permits, all new breakers, and etc would cost WAY more than just swapping a few breakers. Especially since the new panel will likely not be about to see 50-60 Murray breakers. No?

 

[Sophias_dad]

There just isn't enough space in that panel unless you start combining circuits. Even if you replace that 20A breaker with a tandem, that gets you exactly one more circuit, and not even a 240V circuit. It sounds like you want to add a 30 amp dryer outlet to this already stuffed box, and its unclear if you also want another 240V outlet/connection for EV charging.

You >might< be allowed to put MP series breakers in that panel, I see an MH-T breaker(model number actually starts with MP) in there, and other Murray panels say they support EP and MP breakers, so there's a chance yours does too. There should be a label on the backside of the door.

And the final nail in the coffin is that that panel is already at or beyond its load limit. 100A coming in, 50 amps going out(ya, I know its not continuous, and its probably not really a 50A load) but there's like 10 other circuits on each leg of that 100A, and you are asking for another 30A and another??A for EV charging?

The cheapest path is probably a subpanel out near where your new dryer outlet will be, driven by a ~50A breaker that's taken partially from the 20 amp you are swapping with a tandem, and partially from stealing a half-space by combining two 20A circuits you already have, then put a 30 amp or whatever breaker(s) are desired in the new subpanel. If its anywhere near your garage, you'll want to wire it as if its a 75A panel or more, even if its only breakered at smaller level for now.

 

[jeremymc7]

There just isn't enough space in that panel unless you start combining circuits. Even if you replace that 20A breaker with a tandem, that gets you exactly one more circuit, and not even a 240V circuit. It sounds like you want to add a 30 amp dryer outlet to this already stuffed box, and its unclear if you also want another 240V outlet/connection for EV charging.

You >might< be allowed to put MP series breakers in that panel, I see an MH-T breaker(model number actually starts with MP) in there, and other Murray panels say they support EP and MP breakers, so there's a chance yours does too. There should be a label on the backside of the door.

And the final nail in the coffin is that that panel is already at or beyond its load limit. 100A coming in, 50 amps going out(ya, I know its not continuous, and its probably not really a 50A load) but there's like 10 other circuits on each leg of that 100A, and you are asking for another 30A and another??A for EV charging?

The cheapest path is probably a subpanel out near where your new dryer outlet will be, driven by a ~50A breaker that's taken partially from the 20 amp you are swapping with a tandem, and partially from stealing a half-space by combining two 20A circuits you already have, then put a 30 amp or whatever breaker(s) are desired in the new subpanel. If its anywhere near your garage, you'll want to wire it as if its a 75A panel or more, even if its only breakered at smaller level for now.

There's a few 15/20 breakers that are no longer used so I shouldn't have to combine anything. But if I did all my lighting is low power. All the light in my house can be run off one 20A breaker these days.

Either way once I get rid of the double, replaced with a slim and remove (or merge) on slim there is enough room for the 240V. I only need one. The 50A you see in there is for the kitchen electric range.

The 30A 240V was previously hooked up but was disconnected during the kitchen remodel 20 years ago.

Most of the panels draws nothing. Tje heat is GAS and theere is no AC. The lights are all low power LED. Even the dryer and water heater are GAS.

Honestly not worried about tripping 100A load; though I get it looks maxed out.

I've thought about the subpanel in the garage which is other wise of the house. Always moving to 50A instead of 50A. but going to add up quicky again with the extra box, conduit, heavy gauge wire, new breakers.

Not going to stay here and looking to do the bare minimum on the cheap.

There is no real sticker in the box. Even the last SEC certificate is from 69.

Additional photos added.

 

[Sophias_dad]

There's a few 15/20 breakers that are no longer used so I shouldn't have to combine anything. But if I did all my lighting is low power. All the light in my house can be run off one 20A breaker these days.

Either way once I get rid of the double, replaced with a slim and remove (or merge) on slim there is enough room for the 240V. I only need one. The 50A you see in there is for the kitchen electric range.

The 30A 240V was previously hooked up but was disconnected during the kitchen remodel 20 years ago.

Most of the panels draws nothing. Tje heat is GAS and theere is no AC. The lights are all low power LED. Even the dryer and water heater are GAS.

Honestly not worried about tripping 100A load; though I get it looks maxed out.

I've thought about the subpanel in the garage which is other wise of the house. Always moving to 50A instead of 50A. but going to add up quicky again with the extra box, conduit, heavy gauge wire, new breakers.

Not going to stay here and looking to do the bare minimum on the cheap.

There is no real sticker in the box. Even the last SEC certificate is from 69.

Since I see an MH-T breaker in there, and it seems to fit, I'd assume any MP series breaker would fit as well. I'm not an electrician.

I'd be changing that funky one in the upper right, and changing/combining as needed to put another MH-T in there to get the circuit you want.

If you are planning to put in an outlet for an EV, its technically supposed to be driven by a GFCI(either in this panel or a subpanel). That requirement is frequently ignored unless you are getting it permitted/inspected.

 

[Cosmacelf]

Am I reading the dates correctly? 1969? So you’re telling me you’re fine with a 54 year old panel and breakers? If it were me, I’d take this as a hint from the universe that this is the perfect time to upgrade to something that will actually work should a short circuit appear somewhere in your older house. Bite the bullet and do a complete panel upgrade with brand new breakers.

 

[jeremymc7]

Panel is likely from 69. House was rewired at some point with 20A solid copper. At least half the breakers are 10-15 year old due to my kitchen remodel, including new wire to to and in kitchen. Likewise plumbing was replaced at some point to copper supply as well.

I wish the house had 3 wire grounding but I’m not going to rewire the whole house just to add it.

 

[jeremymc7]

Any recommendations that service the Long Beach, CA area.

 

[SageBrush]

If the only issue is space for breakers then an MLO sub-panel adjacent to your current panel solves the problem and is a LOT cheaper and simpler than an MBR swap