Garage Wiring Fire

[howardc64]

This thread taught me a great deal of info and I think its fair to conclude the following

- Charging at 10/20kWhr is a lot of current running in most people's homes. Probably the biggest current draw in the house continuously for a reasonable long period of time and often during sleeping hours no less. There is a thread on here showing pictures of the power meter at 50kWhr draw... that meter was spinning fast!

- This much current draw means any high resistance in the circuit have the potential to produce a lot of heat. High resistance is mostly due to either improper installation, wiring specification, improper contact (say the NEMA 14-50 adapter into the socket), or worn contacts. As FlasherZ noted in post #9/#29, any defect while pulling this much current continuously has a much greater chance of heat/fire compared to your typical wiring/sockets at home.

Given the possible damage risk from any defect in the circuit, what precautions should we take?

1. Properly SPECed wiring/equipment with proper installation. Pros/experienced folks are necessary here
2. Constant monitor of temperature near the UMC/14-50 plug is probably a highly desirable safety measure
3. Avoid frequent plug/unplug any part of the circuit to minimize chance to cause an improper high resistance contact. Using HWPC or leaving the UMC plugged into the socket most of the time is probably a good idea. UMC's portability feature might give a false sense of security. There is a lot of current flowing through the connection so preferably not mess with it all the time.
4. Avoid dangling the UMC from the socket and let gravity tug on the adapter/socket to cause a high resistance contact.

Any other precautions to take beyond these? Maybe a fire extinguisher nearby for good measure if problems shall occur (per Hybris in post #28)

Non of this is directly related to Tesla specifically of course. These issues are related to EVs in general due to the need to pull this much current continuously at home. Maybe Tesla could suggest to avoid unplug/plug the UMC all the time as a precaution. But Tesla probably would assume too much legal liability to make this recommendation.

 

[CalDreamin]

EVSE charging stations installed in 2013 are eligible for a 30% federal tax credit, not to exceed $1000. This tax credit expires on Jan 1, 2014.

 

[gardnerep]

Service Upgrade

Recently had the house electrical service upgraded from 150 amp to 300 amp with a dedicated 100 amp circuit with #2 gauge wire ran for a HPWC. Don't think I will have a concern about the eletrical service being overloaded.

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For that reason I own 2 of the NEMA 14-50 adapters for my UMC. I leave the adapter in the wall and disconnect the UMC at the adapter before throwing it into the tote bag in the trunk. Thus essentially no fatigue from insertion-removal of the adapter.

Is there a heavy duty version of the 14- 50 outlet made to deal with daily cycling? Given the growing number of EV's out there, there would be a market for one to be made.

 

[jerry33]

Is there a heavy duty version of the 14- 50 outlet made to deal with daily cycling? Given the growing number of EV's out there, there would be a market for one to be made.

Hubbell HBL9450A

 

[widodh]

Why would anyone unplug their UMC and bring it with them every day? I suppose there are those that commute hundreds of miles a day, but I can't imagine that's very common. If I needed to (for some reason) bring a UMC with me every day I'd spend the $650.00 and buy another one to keep in the car. No way I'd drop $1200.00 for an HPWC when a UMC can top off my car in about 2 hours for half the price. The UMC was designed to be used every day and it's more than enough for most people's overnight charging needs. For my purposes, an HPWC would be a waste of money and it would have to be removed when I sell the house. With a 220 Volt outlet, future EV Owners can just plug-in.

Why not buy a regular EVSE with a Type 1/J1772 connector? That will fit on every EV and doesn't have to be removed should you move since the new owner can charge his EV with it.

 

[jerry33]

Why not buy a regular EVSE with a Type 1/J1772 connector? That will fit on every EV and doesn't have to be removed should you move since the new owner can charge his EV with it.

The adapter is a pain to use.

 

[Vexar]

Why not buy a regular EVSE with a Type 1/J1772 connector? That will fit on every EV and doesn't have to be removed should you move since the new owner can charge his EV with it.

I hired an electrician to install my NEMA 14/50 and paid $250 for the whole job. You can't get a J1772 charging station for that price, let alone its more complex installation. For the same reason I didn't think an HPWC was necessary, either. I'm happy to leave behind a $20 outlet.

 

[wraithnot]

Why not buy a regular EVSE with a Type 1/J1772 connector? That will fit on every EV and doesn't have to be removed should you move since the new owner can charge his EV with it.

A standard 30 amp J1772 is not fast enough to completely recharge an 85 kWh Model S overnight. A 14-50 at 240 volts can completely charge an 85 kWh Model S in about 8.5 hours. The public J1772s I've used would has taken 15 or 16 hours. If a home EVSE is 240 V instead of ~200 V it would still take something like 13 hours to fully recharge. That is unacceptable for a road trip or back-to-back day trips.

 

[ZBB]

I can't imagine anyone charging with just a single UMC, removing it from the receptacle each day when they leave. That is a lot of wear/tear on the receptacle.

I only have a single UMC -- but it don't remove it each day when I leave.

It's only been unplugged 6 times in just over 6 months. One of those times wasn't necessary -- it was for a day trip that had plenty of charge remaining when we got home.

 

[RainmakerJL]

EVSE charging stations installed in 2013 are eligible for a 30% federal tax credit, not to exceed $1000. This tax credit expires on Jan 1, 2014.

Is this just for labor or for the actual unit? I biught the hpwc.... Would love extra coinage back...

 

[RainmakerJL]

Recently had the house electrical service upgraded from 150 amp to 300 amp with a dedicated 100 amp circuit with #2 gauge wire ran for a HPWC. Don't think I will have a concern about the eletrical service being overloaded.

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Is there a heavy duty version of the 14- 50 outlet made to deal with daily cycling? Given the growing number of EV's out there, there would be a market for one to be made.

I have a 3 year old house. The breaker panels are in the garage. I had a new 100amp breaker put in by the same electricisn who wired the house. I cant imagine i should have any of these concenrs right? I paid for high speed charging. Seems over kill to put the charge down to 40amp or lower out of fear. This thread has me flipping the breaker after charging which is pretty easy since its all in the same area....

 

[Dave EV]

Circuit breakers are not rated for switching duty. Switching them off/on frequently will wear them out. There really is no reason to switch the circuit off when not in use.

 

[widodh]

A standard 30 amp J1772 is not fast enough to completely recharge an 85 kWh Model S overnight. A 14-50 at 240 volts can completely charge an 85 kWh Model S in about 8.5 hours. The public J1772s I've used would has taken 15 or 16 hours. If a home EVSE is 240 V instead of ~200 V it would still take something like 13 hours to fully recharge. That is unacceptable for a road trip or back-to-back day trips.

Ah, but aren't there 70A J1772 EVSEs out there? But that's not really the discussion here

I have a 3 year old house. The breaker panels are in the garage. I had a new 100amp breaker put in by the same electricisn who wired the house. I cant imagine i should have any of these concenrs right? I paid for high speed charging. Seems over kill to put the charge down to 40amp or lower out of fear. This thread has me flipping the breaker after charging which is pretty easy since its all in the same area....

Don't freak out, nothing to worry about. When there is no load on the wires nothing will happen.

 

[dhrivnak]

Seems over kill to put the charge down to 40amp or lower out of fear.

I typically charge at 40 amps, mainly due to a study done by Tom Saxton that showed if you charge at high rates you actually lose efficiency as the system will spend more energy in cooling. If you charge at a low charge rate then you lose efficiency with the cooling pumps. 30-40 amps was highest efficiency.

But there is another bonus in that slower charging is easier on the grid. The power company has greater challenges when large loads come onto the system. Since 40 amps will ALWAYS give me a fully battery I charge at that lower rate. On the very rare occasions, when I need the higher power it is easy to change.

I also defer charging until later at night again trying to be easier on the grid so I charge when they have surplus power.

I do not want to give EV's a bad name by contributing to overloaded transformers in neighborhoods. The neighbors and press would have a field day with that.

 

[pilotSteve]

If you move, take the HPWC with you. Replace the 100A breaker with a 50A and mount a 14-50 outlet in place of the HPWC. To each their own but I find the HPWC an elegant solution to my everyday charging and use the 80A 55-mph charge rate occasionally which totally eliminates range anxiety.

Why would anyone unplug their UMC and bring it with them every day? I suppose there are those that commute hundreds of miles a day, but I can't imagine that's very common. If I needed to (for some reason) bring a UMC with me every day I'd spend the $650.00 and buy another one to keep in the car. No way I'd drop $1200.00 for an HPWC when a UMC can top off my car in about 2 hours for half the price. The UMC was designed to be used every day and it's more than enough for most people's overnight charging needs. For my purposes, an HPWC would be a waste of money and it would have to be removed when I sell the house. With a 220 Volt outlet, future EV Owners can just plug-in.

 

[bareyb]

If you move, take the HPWC with you. Replace the 100A breaker with a 50A and mount a 14-50 outlet in place of the HPWC. To each their own but I find the HPWC an elegant solution to my everyday charging and use the 80A 55-mph charge rate occasionally which totally eliminates range anxiety.

Yeah… no. I'd just as soon unplug my UMC and leave it at that. The last thing I want to do when I'm moving is hire an electrician to come in and remove something I paid to have put in... and being able to charge faster wouldn't gain me anything. I don't even use the full 40 Amps my UMC is capable of (I run it at 30) and it still only takes a couple of hours to top me off.

Bottom line for me is the HPWC costs considerably more to install, and costs an additional $1200.00 to purchase separately. The UMC was included free with the car and serves my needs quite well. I'm glad you like your HPWC and it's a neat looking piece of hardware, but in reality I can't think of a single good reason why I'd ever buy one. It's adds considerable expense to an already obscenely expensive car, and provides no real World advantage for most typical users. It would be much cheaper to buy a second UMC for the car and leave the free one plugged in at home. You would be able to leave the one in the garage plugged in at all times, and you'd have a back up unit in case the one in the garage ever needed a repair.

 

[ecarfan]

I have the HPWC for my S85 and am glad I do. My work schedule is irregular and my work locations in the San Francisco BayArea vary from a 55 mile roundtrip to over 200 miles. I need to be ready to drive at any time. For me the HPWC is worth it.

I ca understand that for people with fixed, regular commutes the HPWC is unnecessary.

I am quite pleased that the Vacaville SC is up and running!

 

[widodh]

Yeah… no. I'd just as soon unplug my UMC and leave it at that. The last thing I want to do when I'm moving is hire an electrician to come in and remove something I paid to have put in... and being able to charge faster wouldn't gain me anything. I don't even use the full 40 Amps my UMC is capable of (I run it at 30) and it still only takes a couple of hours to top me off.

Bottom line for me is the HPWC costs considerably more to install, and costs an additional $1200.00 to purchase separately. The UMC was included free with the car and serves my needs quite well. I'm glad you like your HPWC and it's a neat looking piece of hardware, but in reality I can't think of a single good reason why I'd ever buy one. It's adds considerable expense to an already obscenely expensive car, and provides no real World advantage for most typical users.

I fully understand your reasoning, but the problem with the UMC is that it doesn't safeguard bad users to do dangerous things with it.

You in your case have limited the charging to 30A which is good, but my fear is that there are a lot of ticking time bombs out there waiting to explode.

UMCs plugged into old sockets or poorly inserted into the socket. Slowly wearing out due to every day plugging in and out. I'm not saying they will melt tomorrow, but it could be in one year or maybe two years.

A second UMC which is always plugged in is just fine, but it shouldn't be removed every day or even multiple times a day (charging at work for example). Usually those sockets aren't used for continues high loads over multiple hours.

 

[cwerdna]

I typically charge at 40 amps, mainly due to a study done by Tom Saxton that showed if you charge at high rates you actually lose efficiency as the system will spend more energy in cooling. If you charge at a low charge rate then you lose efficiency with the cooling pumps. 30-40 amps was highest efficiency.

But there is another bonus in that slower charging is easier on the grid. The power company has greater challenges when large loads come onto the system. Since 40 amps will ALWAYS give me a fully battery I charge at that lower rate. On the very rare occasions, when I need the higher power it is easy to change.

I also defer charging until later at night again trying to be easier on the grid so I charge when they have surplus power.

I do not want to give EV's a bad name by contributing to overloaded transformers in neighborhoods. The neighbors and press would have a field day with that.

And guess what? Most other EVs (w/o Tesla hardware) have on-board chargers that can do only 30 amps @ 240 volts maximum anyway.

Some, like the '11 and '12 Leaf have only 3.3 kW on-board chargers. I've seen them pull ~3.7 kW out of the "wall" per the displays on Chargepoint EVSEs we have at work (that run at 208 volts).

I've seen Chevy Volts charge and they seem to pull only ~3.1 (or was it 3.1 to 3.3) kW on the same Chargepoint EVSEs. I presume the Spark EV is the same.

 

[digitaltim]

Indeed. A Model S with Twin Chargers is like adding 4 homes to the local distribution system from a capacity planning point of view. The reason is the lack of diversity with EV charging loads. Most loads in the home cycle on and off. The oven gets up to temp and cycles. Electric heat cycles. Water heaters cycle. Utilities plan on a certain diversity in loads, meaning that not everything in everyone's home will all be on at the same time. But EVs come on full power for the entire charge cycle. Add a couple of these to a local distribution transformer and you've got trouble if it isn't upgraded. Having said this, most utilities are happy to upgrade infrastructure to capture the extra revenue they'll realize. There are exceptions: in some cases, larger pad-mount transformers may not fit on existing bases and civil work is required. Smart Grid technologies like controllable chargers are just starting to be explored.

Spot on...4-5 Tesla's charging in the area and you have matched the typical 200A service of a dual-fuel home.

Lack of load diversity on the distribution grid is going to be problematic - even more so due to cold load pickup issues during sustained power outages. While I am no longer in the energy business, that is the one that has me concerned.

SmartGrid technologies definitely have a place here. We had an interest in a company that built software to aggregate residential load for active demand-side management - perfect for chargers.