Amazed at how dangerous this square d panel is

hi guys,
I was inspecting another 1950s house today in southern california.
In all my years as an IBEW Electrician and the 9 years I have been doing home inspections, I have never seen or dealt with this panel.
It is a square d model number: QO56MRO panel. This panel is original to the home I found it in, which is built in 1957.
As I was taking off the front panel cover of this unit, boom bang !! the cover shorted against the two main bus feeds which are completely open to the panel front.
Unbelievable construction of this panel.
What were they thinking ?
The two hot busses from the meter are exposed to the front cover as you are taking it off.

Just a warning to anyone that encounters this type of panel…It is dangerous in my opinion to even remove the cover.

Kevin Rea
AV Home Inspectors
Palmdale, Calif.

You’re fortunate to be telling the story Kevin. Thanks for posting.


Thanks for sharing Kevin. This is another instance where the “culprit” is not FPE or Zinsco. That’s why we should always be diligent when removing covers - regardless of the panel manufacturer.

I assume this cover tips inward at the top and out at the bottom to remove it? Those types of covers always make me nervous because you never know how the last guy left the wiring inside. I’m thankful you’re here to share the tale.

This has happened to me before and I was not wearing any rubber gloves. Curious if you had any safety equipment on.

Hey John, what gloves do you(or others) use?

hate when that happens
glad you’re able to post this info

received a pair of these during the freebie introduction

they’ve worked so far

Let me start this post with a short prayer of thanks that you are here, Thank you Lord.

I don’t know how many times I have been on my soap box preaching that NO ONE should ever open a panel while it is energized. This is any panel.

When I am called to do any type of work on a service panel THE POWER IS OFF!!!
I have been working in the electrical trade for 44 years and the power goes off before I remove a panel cover even if this means pulling the meter. Clocks be damned

If this is a problem with someone then I pack up and leave. MY SAFETY IN MY RESPONSIBILITY!!!

If you are not worried about your personal wellbeing at least be worried about what it would cost to replace that panel. No more damage than what was done in that picture any court in this nation will order that that panel be made whole. In other words it could end up costing to either have that panel repaired or replaced.

The good Lord was kind to you this time but next time he might be busy helping someone else and then you will have a very sad family. Please be careful


I know this is outside the scope of most HI jobs but I hope this link makes at least someone think

The cover on this panel doesn’t require “tipping” to be removed, it can be pulled straight out.

The problem is that it can be difficult to grasp well enough to pull it straight out, so it’s almost inevitable that it will tip to some degree.

Tipping a cover will get you in trouble.

You must pay careful attention when removing a dead front.


I don’t know what happened in this case but we can all be thankful no one was injured or worse.

I like to open the door and use that as a “handle” to try and prevent tipping.

These help prevent metal contact, I have one that I use all the time.
I think I’ll get a second one:shock:


I’ve got a pair of those but I loose too much “feel” for what’s going on.


Thanks for sharing Joseph.

Had ionization of the air between those two copper conductors occurred the outcome may have been very tragic.
Once the arc started through ionization of the atmosphere the only overcurrent device to open would have been the drop out fuse on the primary of the supplying transformer. The arc would have continued until either the primary overcurrent opened or the arc extinguished itself by burning away the conductors and possibly the current carrying metal of the enclosure.

This can occur rapidly in which case there will be an explosion and melted metal will be flying and the percussion of the blast will hit you like a mule kick or it could burn away slow like a welder burning his welding rod in either case there will be blinding light.

The one thing to keep in mind is that you will be turning screws in an enclosure where there are non-fused service entrance conductors. Anything can happen!

People I beseech you while down on one knee, please be safe. In all my years of seeing people hurt while working with electricity I have yet to talk with even one of them that planed on getting hurt. Please make your plans to not get hurt, safety, safety, safety. Remember Old Smokey, he said, “Only you can prevent forest fires.” Let’s take a lesson from him and say, “Only I am responsible for my safety.”

Do most of you guys open isolated main disconnects? I’m torn on whether to do it every time I am faced with them.

glad you’re OK Kevin.

What Joseph mentions is a good reminder about not being complacent, for sure.

I would say that of the few times I’ve removed dead fronts without gloves and glasses, I’ve felt stupid about it. In my area, the utility company technicians wear a decent amount of PPE and a full face shield just to set a meter… I’m sure they have good reason.

The panel makers should make a lip the deadfront can rest on while taking the screws out. You almost need three hands to pull the last two screws and hold it to the panel and pull it out without tipping… I usually wear gloves. They have rubber but not completely rubber.

Just did an inspection today with a square D. House was built in 1977 so I can only assume that is when the panel was installed…No there was no stickers or engraving anywhere on the box, just the main breaker was marked square D. It was put together in such a way that I couldn’t even see the service lines coming in to the main, couldn’t trace the grounding rod, it went through the back of the box under the house somewhere that I could not find. And as far as taking the front panel off, thank you Nachi for the wonderful magnets. I would never have got the panel off with out them.

Hello Everyone,

As stated, it is always important to never get complacent when dealing with electrical equipment. While the design appears to be less than perfect it obviously was acceptable at one point for a very reputable manufacturer. This only goes to show not matter what the make, model and design of an electrical product you always have to be ready for the unexpected. Remember to ticker[and I am sure you all know what that means] any panel you intend to open and always assume live unless otherwise known.

I have been working with electricity for over 25 years and I can tell you I have just as much respect for it now as I have ever had. In regards to the magnets, I took some heat for those when I promoted them but I can tell you I still believe in them for certain specific applications as stated in the video where I promoted them…not surely as a CURE all by any means.

I am just glad the original OP was ok and was able to share…again I like to think I know a little about electrcity and one thing I know is that it can kill without any remorse.

Take care everyone…nice to stop in and see that safety is still KING !