Temporary / Emergency charging via direct attachment to the Electical Panel

[freds]

Well I guess I am generating entertainment!!!

"And yet it moves" or "Albeit It does move" (Italian: Eppur si muove; [epˈpur si ˈmwɔːve]) is a phrase said to have been uttered before the Inquisition by the Italian mathematician, physicist and philosopher Galileo Galilei (1564–1642) in 1633 after being forced to recant that the earth moves around the sun

PS. It works.....

 

[green1]

TEO makes a valid point, it is always good to know what the laws are so that you can weigh the risk vs benefit. In modern society most people break many laws on a routine basis, but each person needs to decide for themselves which ones are worth the risk for the benefit. In this case I personally would still not hesitate to do this assuming it was a safe location where there is no risk to others or myself. Electrical inspectors don't spend their days knocking on random doors to check house wiring.

 

[roblab]

Ah, here we go with fear and misunderstanding.

Having wired several homes and a warehouse or two, in a state that allowed the owner to do so, not being an "electrician", but considering myself reasonably intelligent, I have done the same thing. I don't recommend it to those who don't understand it, but I seems silly to cry "fire" and "electrocution". This set up is safe. Laying your hands on a circuit breaker panel with the cover off is not as dangerous as it might seem. The wire connections are recessed and the buss bar is under the circuit breakers. You'd have to reach your pinkie down underneath, and I could envision times when one could reach both sides of a live plug if you tried hard enough.

If someone is able to wire up a 14-50 in a pinch (as I did when visiting relatives in another state) for a necessary charge, and who, obviously, did a careful and neat job, I say, more power to him, and to his Tesla.

To those of you who are fearful, or who are more concerned about violating laws meant to protect the uninformed, Don't Do This At Home.

 

[FlasherZ]

I imagine FlasherZ will have some choice words about this...

FlasherZ is a bit speechless. Even temporary connections are required to follow the code, and this is fraught with risk.

Some people, however, have no problems with the electrical equivalent of extending a natural gas line to their dryer using duct tape and a garden hose - if they care to accept the insurance and liability implications, good luck.

My biggest issue here is telling someone else to do it this way. IT IS NOT SAFE AT ALL.

 

[FlasherZ]

Some thoughts, now that I look closely...

The conductors are applying torque to your breakers which can pull them loose from the bus bars and/or create an arcing hazard. Your conductors coming straight out of the box can be cut on sharp edges (hence requirement for bushings on box exits and why large conductors shouldn't enter the boxes on the far margins - breakers should never support the full weight of conductors). Want to make that safer? Put some bends in your conductors to come directly out from the breaker, then support them on something. Use shrink wrap or tape where the wires are likely to rest against the box to avoid insulation nicks or cuts.

As noted above, you have an alphabet soup of breakers in that box. I see breakers of type HOM (Square D) and BR (Murray nee Bryant), and you added a type Q (Siemens). Most of these are 1" breakers that are "close enough" and will work (GE THQL's are similar). Bad news is that not all panels are made for all brands - check your cover for appropriate breaker listing in that panel. Occasionally, the slightly larger GE/Siemens/Homeline breakers will crowd out a Murray panel and place stress on the bus bar, or the cover won't fit on..

In addition, the panel's deadfront cover is more than just a protection cover for wandering hands - it physically holds the breakers in place, limits the stress on the bus bar from conductors, and limits the potential for arcing that could start a fire. If I were doing a temporary install, I'd use a 3/4" knockout at the bottom of the panel (with a small nipple and bushings to guide the wires out), and put the deadfront panel back on. I'd use blanks to cover the breaker space that remained open when finished, and a plug to cap up the knockout. It's still not to code and subject to risk, but is much safer.

Your ground is too small and that spring clip limits effective fault protection. #10 is required for any circuit protected by a 30 to 60 amp OCPD and that clamp is dangerous. At a minimum you should also connect the neutral, even if you remark a black or red to do so (against code).

I stand by my statement that this is unsuitable. I might consider it if I were in need of something in an emergency only, but would be used one time only and supervised closely the entire time. More than once? You're doing it wrong... and please don't advise people do this at all... even temporarily.

 

[FlasherZ]

PS. It works.....

So does extending a gas pump nozzle via rubber tubing and aluminum hose clamps.

Just because it works does not mean it's safe.

 

[GabrielB]

So does extending a gas pump nozzle via rubber tubing and aluminum hose clamps.
Just because it works does not mean it's safe.

And if the rubber hose is tight enough you don't even need a hose clamp - just blow real hard on the hose first to test for leaks. So says my friend's late uncle Vern...
The gas pump quote has to be a joke, as the pump nozzle's anti-top-off sensor would constantly trip. Don't do it!

In reference to this "emergency charging" technique: (def: a serious, unexpected, and often dangerous situation requiring immediate action. Immediate action taken in the interest of protecting life or property.) It is an "opportunistic jury-rig", NOT an Emergency. In fact, this jury-rig could easily create a real emergency.

But let's compare this electrical jury-rig to other similar vehicular urgent conveniences. We have all seen people who have run out of gasoline use plastic milk bottles or glass bottles, both without funnels, spilling gas down the side of their car or lawnmower (mouth siphoned from car) to fill their dead cars, lawnmowers, or boats. So how is the "opportunistic jury-rig emergency charging technique" any worse than what gas people do every day? There is no good answer. Just don't do it.

One more personal soap box thing: The NEMA 14-50R receptacle will accept up to 4AWG copper wire. With 50Amp breakers, the 80% continuous permissible load is 40Amps. The receptacle WILL get warm/hot. Your best protection is to use 4AWG copper wire (well torqued!) to keep the NEMA 14-50R as cool as possible. Using 6AWG or 8AWG (or horrors of horrors aluminum wire) WILL result in a hotter receptacle and UMC. Also, the NEMNA 14-50R requires a minimum of 8AWG for the ground wire. NOT 12AWG with a battery clamp!

Whether you are doing a clean permitted install OR jury-rigging, please use 4AWG copper with a NEMA 14-50R or any other 50Amp receptacle.

 

[FlasherZ]

Also, the NEMNA 14-50R requires a minimum of 8AWG for the ground wire. NOT 12AWG with a battery clamp!

Whether you are doing a clean permitted install OR jury-rigging, please use 4AWG copper with a NEMA 14-50R or any other 50Amp receptacle.

Incorrect on the ground wire. NEC table 250.122 - #8 is only needed when OCPD is between 61-100A; #10 is needed when OCPD (breaker) is between 21-60A. All copper, of course - AL is different.

#6 is sufficient for the ungrounded conductors as it is rated by the NEC (table 310.15(B)(16)) to 65A for 75 degree terminations (most commonly found today). That easily covers the 50A rating requirement for 40A continuous loads. #8 will work just fine as long as it is not NM cable (see NEC 334.80), as it has a 75 degree ampacity rating of 50A.

Even at 40A continuous loads a receptacle should not get hot - that is an indication of a problem. It may get warm, but certainly not hot to the touch. No need for extreme overkill.

 

[newdev]

Use #6 Wire as it is not much more money than the #8 you used and it is better for 40amp constant load. # 8 is minimal but # 6 is optimum.

 

[FlasherZ]

Use #6 Wire as it is not much more money than the #8 you used and it is better for 40amp constant load. # 8 is minimal but # 6 is optimum.

That's my recommendation as well (see the FAQ in my signature), but I address what's to code and what is not.

 

[Tedkidd]

...and maybe set the car to 30...

 

[GabrielB]

Incorrect on the ground wire. NEC table 250.122 - #8 is only needed when OCPD is between 61-100A; #10 is needed when OCPD (breaker) is between 21-60A. All copper, of course - AL is different.

#6 is sufficient for the ungrounded conductors as it is rated by the NEC (table 310.15(B)(16)) to 65A for 75 degree terminations (most commonly found today). That easily covers the 50A rating requirement for 40A continuous loads. #8 will work just fine as long as it is not NM cable (see NEC 334.80), as it has a 75 degree ampacity rating of 50A.

Even at 40A continuous loads a receptacle should not get hot - that is an indication of a problem. It may get warm, but certainly not hot to the touch. No need for extreme overkill.

I stand corrected on the #8 ground wire. Thank you. However, I will continue to recommend #4 copper for the ungrounded conductors for long runs (75+ feet) through a hot summer attic (140degF) as was my case when installing the NEMA 14-50R. Even for short runs, when charging at 40Amps continuously for 5 hours, a #8 wired NEMA 14-50R will get allowably hot, a #6 will get noticeably warm, and the #4 may warm slightly. At this point the pins in the UMC are the bottleneck, assuming the terminals in the NEMA 14-50R are properly torqued. When I later got the HPWC, I replaced the #4 with #2. #3 may have been ok, but again going through a hot summer attic for 75+ feet the #2AWG copper gave more margin and less power loss when running 80Amps continuously.

In the last 8 months my PG&E drop-line has arced & vaporized twice and fallen once while charging at 80Amps, but my house and Tesla wiring is just fine. So I am happy with my extreme overkill, and PG&E has finally installed a proper new and larger drop-line.

 

[FlasherZ]

However, I will continue to recommend #4 copper for the ungrounded conductors for long runs (75+ feet) through a hot summer attic (140degF) as was my case when installing the NEMA 14-50R. Even for short runs, when charging at 40Amps continuously for 5 hours, a #8 wired NEMA 14-50R will get allowably hot, a #6 will get noticeably warm, and the #4 may warm slightly. At this point the pins in the UMC are the bottleneck, assuming the terminals in the NEMA 14-50R are properly torqued. When I later got the HPWC, I replaced the #4 with #2. #3 may have been ok, but again going through a hot summer attic for 75+ feet the #2AWG copper gave more margin and less power loss when running 80Amps continuously.

Your choice, of course, but my opinion is that recommendation is quite overkill.

First, I think your estimation of 140 degrees ambient in an attic is a bit high. Even in my midwestern US home, with summer temps considerably higher than the SF bay area, proper construction (ridge vents, louvered gable vents, etc.) means my attic doesn't exceed 120 degrees. But I'm happy to assume your figure. In the case of attic runs, #8 may not be sufficient when you take into account ambient correction and they shouldn't be used there.

NEC table 310.15(B)(2)(b) lists correction factors for ambient temperature. For 60 deg C (140 deg F) ambient temperature, 90 deg C conductors have a correction factor of 0.77. 0.77 x 75A (#6 ampacity for 90 degree conductor) is 57.75A rating. Plenty of room.

Regardless of whether you use #8, #6, or #4, the none of these will get any warmer than the smaller total conductor size used in the UMC's cord anyway. Really, it's overkill - but if you're happy with it, that's all that matters. The NEC's guidelines have appropriate tolerances and allowances built-in, no need to overbuild.

In the last 8 months my PG&E drop-line has arced & vaporized twice and fallen once while charging at 80Amps, but my house and Tesla wiring is just fine. So I am happy with my extreme overkill, and PG&E has finally installed a proper new and larger drop-line.

PoCo connections aren't governed by NEC, PoCo's have their own standards on a per-state basis. My 400A home service is provided by a 350 kcmil AL cable, which is rated by the NEC for only 280A. My former 200A home service was provided by a 2/0 AL cable, which is rated by the NEC at 135A.

Truth be told, though, the issue is very rarely the conductor size. If you look at "vaporization" failures, there are two major factors: most of the time they occur at splices that have corroded/weakened over time, and most of the rest of the time it's due to some type of shift or construction that compromises the cable's jacket and creates the same corrosion / weakening. In neither of these cases does wire size make any appreciable difference. If you're drawing a load that is melting an intact conductor in the center, you have a serious failure on your hands (likely a direct short with a failure of transformer fuse and main breaker).

My best to you.

 

[GabrielB]

A real pleasure chatting with you FlasherZ,

I should add that my background is high power electro-mechanical mechanisms for Space Systems, and I design for fault tolerance as repairs are not an option. I've seen a lot things fry, and it's the rigorous environmental testing that ferrets out the workmanship, or the unexpected...

Your last paragraph hit the nail on the head. My home was built in 1958 with a 120Amp Zinsco Panel. In 1970 a tree had wore away the insulation on the drop-line, and crimps w/ electrical tape were used for the repair. In 2006 I did an extensive re-model with a new Square-D 200Amp main service panel on the other side of the house. When PG&E was called to move the drop-line I asked that the damaged line be replaced. "Naw" said the linesman, "this'll be ok". Strike One.

March 2009 I ordered my Tesla MS.
Aug 2009 I added a 7kW Solar System.
Sept 2012 I installed the #4 NEMA 14-50R.
Dec 2012 I got my Tesla MS.
Feb 2013 I received the HPWC and replaced the #4 Romex with #2 Romex.

In March of 2013 while charging after 10pm at 80Amps, the old electrical tape on the drop-line crimps failed and shorted to the Neutral vaporizing it lightning bolt style it in less than a second. Phase balance was lost (94V/146V) and the HPWC shut down. House continued to run due to a solid ground system, but the uneven loads threw off the phase balance. I called PG&E in the morning to replace the damaged drop-line. Linesman said "Naw, this is a #2 drop-line. We don't replace these, we repair them." He cut out the old crimps and damaged wire, synched the cable together and added 3 crimps. Since the line was now too tight, he cut the utility pole end and added 2 more feet with 6 more crimps. Turns out the linesman miss-diagnosed the old wire as it was later discovered to be #4. Strike Two (3,4,5, & 6 as far as I'm concerned).

This June 2014 on what was my birthday the Tesla was set to start charging at 80Amps at midnight. At 12:20am we awoke to pounds on the door, fireworks in the back yard, and 5 fire trucks. This time the short at the crimps involved the insulation as the arc-plasma source, and zipped along the power line for 20 feet lighting up the sky for a good 15 seconds before finally parting and falling down in flames. A dozen firemen in my backyard, I was the only one at my party without a hat. They used my garden hose to put out the still burning insulation. The HPWC had isolated and protected itself, and the Tesla.

PG&E showed up at 2:30am, and I begged the linesman, for my birthday, to please give me a new drop-line. Unbelievably, he said "We repair #2's, we only replace #4's." As he went up in his bucket lift, he discovered it was actually a #4 line that had failed, so he removed all of it, and all the crimps, and installed a #2 with heavy clamps to the main distribution line, and to my #00 service entrance. Finally I am a happy camper.

Other folks reading this - The NEC codes, heat rating, and de-rating for wires and cables used in the walls, attic, and conduits of a home or business are much more conservative than what Power Utility Co's use for wire and cable hanging in mid-air where heat can dissipate. A #2 Romex in your house and a #2 Cable from the utility pole are of different design and use a totally different set rules.

So knock on wood, hopefully I will not need to tolerate any more faults

 

[freds]

Saved lots of stress on a recent trip to a resort with my attachment.

Just showed it to the handy man and he says I know where I can attach it, went to their maintenance shed and he pulled the circuit breaker for the baseboard heaters and plugged it in.

No muss, no fuss…

 

[JimmyAZ]

I know that our panel, although having extra slots available, wasn't able to have my NEMA installed due to overloading potential. That may be something to consider before plugging in.

 

[aaronw]

This sounds like typical PG&E incompetence. My parents had a significant gas leak between the street and the meter and it took years of complaining before PG&E finally admitted there was a problem and fixed it.

Recently my father contacted PG&E to change the rate schedule since he has a plug-in and PG&E basically told him he shouldn't charge because the block can't handle the load. This is despite the fact that everything was fully permitted and has been in use for several years. PG&E already has had to fix a couple underground lines in the neighborhood but has been putting off upgrading or replacing it for far too long.

 

[ABCCBA]

[QUOTE="aaronw, post: 1423611, member: 11454"Recently my father contacted PG&E to change the rate schedule since he has a plug-in and PG&E basically told him he shouldn't charge because the block can't handle the load. This is despite the fact that everything was fully permitted and has been in use for several years. PG&E already has had to fix a couple underground lines in the neighborhood but has been putting off upgrading or replacing it for far too long.[/QUOTE] @aaronw Sounds like there won't be any house flippers allowed in the neighborhood since upgrading to a new Stainless Steel GE Profile Double Convection oven may overload the neighborhood. lol

 

[aaronw]

[QUOTE="aaronw, post: 1423611, member: 11454"Recently my father contacted PG&E to change the rate schedule since he has a plug-in and PG&E basically told him he shouldn't charge because the block can't handle the load. This is despite the fact that everything was fully permitted and has been in use for several years. PG&E already has had to fix a couple underground lines in the neighborhood but has been putting off upgrading or replacing it for far too long.

@aaronw Sounds like there won't be any house flippers allowed in the neighborhood since upgrading to a new Stainless Steel GE Profile Double Convection oven may overload the neighborhood. lol[/QUOTE]
There's a neighbor a few houses down doing major house renovation, basically adding on a guest house. I think PG&E will end up being forced kicking and screaming to upgrade the neighborhood. The homes were built around 1969 - 1970 and it was one of the first neighborhoods in the city to have underground power, phone and cable. Most of the homes originally had 100A service. The local transformer has already blown up and had to be replaced (before my father added his EV) twice. The first time they noticed something was wrong was whenever my father turned on his stereo system the voltage at the meter dropped 8 volts and he could modulate the lights with the bass.

 

[Tedkidd]

They could avoid upgrading by offering bonus incentives for solar and powerwalls.