Level 2 charging problem

[Shrink13]

I had an usual experience last night with my three-year-old level 2 charging unit. My much beloved BEV was at the dealer getting the software update and I had a REX loaner. The car was being charged and it was on because I was sitting in it trying to pair my Bluetooth phone. At the same time, the dryer in the house ( on a separate circuit) was on. I did notice that the readout on the dash said that charging would be completed at 4 PM. I thought that was an usual since it was 7:30 PM and it only needed about an hour of charging. All the settings were correct - The charge level was on high and it was set to charge immediately. All of a sudden the charging stopped and electricity throughout the entire house went off. I have lived in this home for over 45 years and have never had the entire house shutdown. The breakers in the garage were all fine, but the two 100 circuit breakers next to the outside meter been tripped.

I am confused as to why the main breakers tripped before the inside individual breakers tripped. I have Charged my BEV many times before with the dryer running with no problem at all. Does the REX draw more power than a BEV? Did it make a difference that the car was on while I was being charged?

Any suggestions or thoughts would be greatly appreciated. Thank you.

 

[jadnashuanh]

Add up all of the breakers in your panel and I'd guess it is WAY more than the size of the main breaker. This is common because rarely would anyone have all of the circuits near max. But, it CAN happen. What you saw is a classic panel overload, and the main breaker did exactly what it was designed to do.

The EVSE sets the maximum available in its pilot signal, and the vehicle uses up to that max amount, if it can. The BEV is no different than the REx in that manner, and is limited to 30A or so at level 2 and about 12A at level 1.

In addition to the dryer and the EVSE, you may have hit the rare situation where the refrigerator just turned on, the washing machine started a spin cycle, someone plugged in the coffee pot, and maybe a hair dryer, etc. or, your wife turned on the oven and had a couple of burners running. Starting surge current on big motors can cause an overload, but a circuit breaker doesn't trip immediately normally. But, if the load is big enough or there is a short, it will almost immediately.

The fact that an individual branch circuit did not trip and the main one did means those individual circuits are fine...the combined power from the whole panel exceeded the main breaker size. It may be time to consider a panel upgrade. 100A is small by today's standards in the USA especially if you have added any creature comforts (like a/c if the house was not built with it).

 

[Shrink13]

Thank you for taking the time to respond Jim and thank you for your information. I found it very helpful and I will give serious consideration to your suggestions.