Should I Stop A Pro Electrician From Working On My Panel HOT?

[TheWizard]

I think so on the assumption that a 60amp breaker is more rugged than a 50...

"More rugged" is incorrect and misses the point.

Since the Tesla wall charger can be configured to draw a maximum of 48 amps, you MUST use a 60 amp breaker or larger and proper wire gauge for the breaker size...

 

[joesxm3]

I had been thinking about conduit. The wall charger has opening for 3/4 inch conduit but can be drilled to accept 1 inch. I was going to offer to pay extra for 1 inch conduit if it made it easier to pull the wire, but the idea of heat build up adds to the benefit of 1 inch conduit.

The wall connector has a 24 foot cable on it to plug into the car. Should that be considered when figuring how long the wire run is?

 

[joesxm3]

"More rugged" is incorrect and misses the point.

Since the Tesla wall charger can be configured to draw a maximum of 48 amps, you MUST use a 60 amp breaker or larger and proper wire gauge for the breaker size...

Agreed. That is basically what the electricians on the forum were saying that they got rejected by the building inspector for not doing.

 

[Midpack]

The wire size must be large enough to handle current rating of the breaker. It doesn't matter what anyone 'plans' to charge at, what matters is what those wires might have to carry before the breaker opens.

Good information. I’m asking because Joe may be adding safety factor on top of safety factor. He’s choosing the highest breaker and wire possible, and that his prerogative though I’d consult an expert directly (vs reading Internet forums). Not sure if he’s planning on copper or aluminum wire.

I have a 50A breaker with 6 AWG copper - seems to be good for 55-65 amps depending on which source you choose. My run is about 8 feet from the panel. I’ll charge the car at 32A, absolutely no need for 40-48A for me. It would be easy to swap to 60A and 4 wire later if needed in my case, but I don’t see that ever happening. Am I wrong?

 

[joesxm3]

I have a 50A breaker with 6 AWG copper - seems to be good for 55-65 amps depending on which source you choose. My run is about 8 feet from the panel. I’ll charge the car at 32A, absolutely no need for 40-48A for me. It would be easy to swap to 60A and 4 wire later if needed in my case, but I don’t see that ever happening. Am I wrong?

According to the article posted by TheWizard, 6awg wire has a 65amp ampicity and you need to divide 50amp breaker by 0.80 which gives 62.5 amps. So 6 awg wire should be fine. Since you are only 8 feet, no need to worry about voltage loss in the calculation. Or so it seems to me.

Although in the Munro video they did say that they would go with 4awg just to be safe for your type of circuit.

But your plan to charge at 32amps leaves wiggle room and the wiring seems to meet code. I imagine that the burned parts were charging at a higher rate than you plan to.

I am planning to use copper wire as it say to in the Tesla manual.

 

[TheWizard]

I have a 50A breaker with 6 AWG copper - seems to be good for 55-65 amps depending on which source you choose. My run is about 8 feet from the panel. I’ll charge the car at 32A, absolutely no need for 40-48A for me. It would be easy to swap to 60A and 4 wire later if needed in my case, but I don’t see that ever happening. Am I wrong?

You may be wrong depending on the specific charger you have installed.

If you download the installation manual for the latest Tesla wall charger and read about the Commissioning Procedure starting on page 28, you'll see the issue.
https://www.tesla.com/support/installation-manuals-wall-connector

The issue is that the breaker size is set in the charger via firmware and can be changed later the same way.
So if someone else (a dimwit) sets it to 60amp breaker and 48 amp current draw, there can easily be a bad situation.

This is why many wiring inspectors won't allow your configuration...

 

[ERD50]

So here's a spec sheet for a typical home breaker, along with the full document for reference.

So if I'm following the lines right, @ 1.25x rated current (50A pulled on a 40A breaker), the breaker would NOT OPEN for 2.5 minutes, and is spec'd TO OPEN within 50 minutes. So for a significant overload, a 2.5 to 50 minute range is pretty wide!

That's part of the reason for the 3 hour 'continuous' de-rating for loads - to avoid nuisance trips, as after 3 hours, you get into the range that the breaker *may* trip at its rating.

click on the "CircuitBreakerChart.pdf" in attached files for a clear version you can zoom in a pdf viewer.

-ERD50

 

[Midpack]

You may be wrong depending on the specific charger you have installed.

If you download the installation manual for the latest Tesla wall charger and read about the Commissioning Procedure starting on page 28, you'll see the issue.
https://www.tesla.com/support/installation-manuals-wall-connector

The issue is that the breaker size is set in the charger via firmware and can be changed later the same way.
So if someone else (a dimwit) sets it to 60amp breaker and 48 amp current draw, there can easily be a bad situation.

This is why many wiring inspectors won't allow your configuration...

I’m a dimwit, I should have noted I am using a Tesla Mobile Connector at 32A. Those instructions call for 50A breaker and 6 AWG copper, checked to comply with code before proceeding. With a 50A breaker, I’d be within guidance for a Wall Connector as well - page 6. It’s a closer call for Joe with a wall connector. Joe and I are both trying to be conservative.

 

[Winemaker]

Some mines have wet zones.
I'd be really nervous about working on an electrical issue while standing in a puddle in a mine.
So it was good that you were certified...

We never worked on live equipment unless troubleshooting, then repairs were made after tagging and locking out. We also had high voltage circuits and gloves; many safety precautions.

But as a few have mentioned above, adding a circuit breaker to a box is a relative easy and safe job for someone who knows what their doing.

 

[freedomatlast]

This thread reminds me of the time we got a new safety director at Megacorp. This person had absolutely no mechanical or electrical experience or ability but proceeded to demand new directives such as "all tool and die makers must wear gloves when running machines" and "no employee will ever open a panel and probe a live circuit on any machine".

Obviously the tool and die makers, engineers and technicians on my team immediately challenged these new directives. Anyone with any experience or common sense knows you don't want gloves or any loose clothing on when running lathes or mills and most times you can't detect what's wrong in a circuit by probing with a multimeter unless the circuit is powered. And yes, actual repairs were made after powering down and locking and tagging out.

I told my guys to continue as usual and I'd deal with new safety director who was replaced a short time later, but not without a huge battle.

As in most things in life, no matter how well intentioned, it's that lack of knowledge and experience that creates unnecessary fear and directives.

 

[ls99]

This thread reminds me of the time we got a new safety director at Megacorp. This person had absolutely no mechanical or electrical experience or ability but proceeded to demand new directives such as "all tool and die makers must wear gloves when running machines" and "no employee will ever open a panel and probe a live circuit on any machine".

Obviously the tool and die makers, engineers and technicians on my team immediately challenged these new directives. Anyone with any experience or common sense knows you don't want gloves or any loose clothing on when running lathes or mills and most times you can't detect what's wrong in a circuit by probing with a multimeter unless the circuit is powered. And yes, actual repairs were made after powering down and locking and tagging out.

I told my guys to continue as usual and I'd deal with new safety director who was replaced a short time later, but not without a huge battle.

As in most things in life, no matter how well intentioned, it's that lack of knowledge and experience that creates unnecessary fear and directives.

A wonderful example of someone acheiving the pinnacle of Peter Principle. Hired [-]Promoted[/-] beyond their competence, in this case of safety.

 

[CRLLS]

When getting a product through UL listing, the size of the recommended breaker is listed in the install instructions. It is sometimes relied upon for evaluating the device fault characteristics. i.e. what happens when part "x" fails. Does it create a hazard or fire? I would not oversize a breaker beyond what the product recommends. Oversizing the wiring is simply a matter of whether the wire will fit the terminal block. In this case "12-4 AWG (3.5 - 25 mm2), copper only" according to the manual.

 

[rrs26ja]

Is he a licensed electrician? If so its his responsibility to ensure his safety. I assume the panel is in the basement which means he has no lights on if the main is shut off. I guess you could always hold a flashlight for him, It shouldn't take long to insert the new breaker, run wires into the panel and make the hook up.

 

[dflowers1]

No, your electrician should not be working on a panel with the main breaker on. That violates OSHA and the NEC.
You also are placing yourself being liable for accident that may occur. I hope your electrician's liability insurance is paid up.

 

[SecondAttempt]

This thread reminds me of the time we got a new safety director at Megacorp. This person had absolutely no mechanical or electrical experience or ability but proceeded to demand new directives such as "all tool and die makers must wear gloves when running machines" and "no employee will ever open a panel and probe a live circuit on any machine".

Obviously the tool and die makers, engineers and technicians on my team immediately challenged these new directives. Anyone with any experience or common sense knows you don't want gloves or any loose clothing on when running lathes or mills and most times you can't detect what's wrong in a circuit by probing with a multimeter unless the circuit is powered. And yes, actual repairs were made after powering down and locking and tagging out.

I told my guys to continue as usual and I'd deal with new safety director who was replaced a short time later, but not without a huge battle.

As in most things in life, no matter how well intentioned, it's that lack of knowledge and experience that creates unnecessary fear and directives.

That's where I am and why I am considering moving up my retirement by about a year, in other words, to now.

 

[Retired Expat]

I know there are some very knowledgeable electrical people here. I'm having a licensed professional electrician with decades of experience put a 250V/50A breaker and receptacle in our house. He did not throw the main switch for the work he's done, but all of that was downstream of the breaker - e.g. conduit, pulling wire, receptacle, etc. - so no real risks. I told him he was welcome to throw the main, he said it wouldn't be necessary.

He's coming back today to install the breaker and make the final tie in. All's left is connecting the ground and wiring to the new breaker and clicking it in to the panel in an existing space, so I'm guessing 5-10 minutes at the most. I told him we'd be prepared for him to throw the main for that, he said again it won't be necessary?

I watched the work he's done so far, and it's top notch - I know from 35 years of watching pros work in industry. The guy is the husband of a friend of DW, otherwise I probably wouldn't even be asking - I'd insist.

I worked in manufacturing my whole career. We would never let any electrician work on a live circuit and followed all lock-out procedures 100% of the time. If any electrician tried to take shortcuts in my presence, I would stop them no ifs, ands, or buts. I have seen residential electricians work briefly on live 125V, and I've felt that jolt by mistake a couple times in my life. But this is 250V/50A in the 200A panel, I have never seen anyone do that before - and it makes me very uncomfortable.

The liability and workmen’s comp claim is going to go against you as the homeowner ultimately so if it makes you worried of course you should insist!

 

[prudent_one]

No, your electrician should not be working on a panel with the main breaker on. That violates OSHA and the NEC.
You also are placing yourself being liable for accident that may occur. I hope your electrician's liability insurance is paid up.

How would the homeowner have any responsibility for such an accident, when a licensed pro was hired to do a job?

 

[OldShooter]

The liability and workmen’s comp claim is going to go against you as the homeowner ultimately ...

Is that your own fact or do you have backup to support the statement?

 

[dflowers1]

How would the homeowner have any responsibility for such an accident, when a licensed pro was hired to do a job?

In most states you have to be a master electrician to get a permit from the AHJ. If he pulls the permit and has the work inspected and has liability insurance, you shouldn't have a problem. Just make sure he has a permit and do not allow him to have you pull the permit as the homeowner, in which case you will be liable for the work.
If you have any doubt, just call the electrical division of your local Building Department.

 

[Winemaker]

Listen, being a certified electrician just means you can legally get electrocuted. You've been trained how to do the work safely and know how and where the hazards are.

 

[m3bs]

I don’t mind swapping breakers myself, but hired a pro to replace a service panel. He told me when I hired him that he would have to pull the meter for a while which means contacting the power company, but he opted to work it hot. I was a nervous wreck, but he pulled it off without incident.

I worked for a company that was extremely safety conscious and would never have allowed that to happen, so it was hard for me to stay back and keep my mouth shut.

 

[JoeWras]

I don’t mind swapping breakers myself, but hired a pro to replace a service panel. He told me when I hired him that he would have to pull the meter for a while which means contacting the power company, but he opted to work it hot. I was a nervous wreck, but he pulled it off without incident.

Holy <bad word!>.

This is one job I think I'd call STOP on the contractor.

When my electrician replaced my panel, he pulled the meter. To pull the meter, he wore long gloves, a face shield, and was standing on a 6" piece of plastic. Great safety precautions, but not needed, and there was no arc flash. But he was ready.

 

[ERD50]

Holy <bad word!>.

This is one job I think I'd call STOP on the contractor.

When my electrician replaced my panel, he pulled the meter. To pull the meter, he wore long gloves, a face shield, and was standing on a 6" piece of plastic. Great safety precautions, but not needed, and there was no arc flash. But he was ready.

So we're talking about disconnecting L1/L2 live, getting them (and Neutral) slipped out through the entry to the service panel, so the service panel can be removed, then reversing that with the new box?

Well, I can see where one could very carefully do the disconnect, and I imagine they have some handy insulated cover/cap for the wire ends (or just tape 'em up - live?). If those caps are robust, then maybe carefully slipping them out and back in isn't all that tough?

With the proper tools, protective equipment, and insulation (I hope he wore safety glasses at least to protect against an arc) and a lot of care, no doubt it can be (and obviously has been) done. But that just doesn't seem worth the risk at all. Just have the meter pulled!

-ERD50

 

[JoeWras]

So we're talking about disconnecting L1/L2 live, getting them (and Neutral) slipped out through the entry to the service panel, so the service panel can be removed, then reversing that with the new box?

Well, I can see where one could very carefully do the disconnect, and I imagine they have some handy insulated cover/cap for the wire ends (or just tape 'em up - live?). If those caps are robust, then maybe carefully slipping them out and back in isn't all that tough?

With the proper tools, protective equipment, and insulation (I hope he wore safety glasses at least to protect against an arc) and a lot of care, no doubt it can be (and obviously has been) done. But that just doesn't seem worth the risk at all. Just have the meter pulled!

-ERD50

It would kind of be like the game "operation." Loosen the lugs, pull the 3/0 gauge wire. You might as well be pulling a rod, and make sure to not contact anything?

Whoopee, what a game!

 

[dflowers1]

You listen, being a licensed electrician is required to do electrical work for others and obtain a permit to do so. If you want to do your own electrical work for yourself and believe you're qualified, go for it.