Circuit breaker tripped last night

[Jeeves]

First time this has ever happened for me, but the circuit breaker tripped on my EO Mini Pro supply last night. It would have been seriously inconvenient if I had a long trip planned today.

I’ve sent an enquiry to EO, but has anyone here had similar experience with their charger and able to suggest anything else I might do beyond calling out the installer to check the installation over?

 

[stonecoldrmw]

Weird that you posted this today after me posting my update regarding my TWC tripping. Hope you get it sorted out.

 

[MrBadger]

What type of circuit breaker tripped - over current or RCD etc?

 

[MadScientist]

My Andersen installer fitted a 40A RCD on my charger. He explained that LR Teslas and Jaguar iPaces can sometime trip 30A ones. I’d be interesed to know what RCD you’ve got.

 

[Generator]

My Andersen installer fitted a 40A RCD on my charger. He explained that LR Teslas and Jaguar iPaces can sometime trip 30A ones. I’d be interesed to know what RCD you’ve got.

Likewise, 40 Amp RCD and MCB on all mine.

 

[MikeHolliday]

If you are using a Tesla Wall Connectors, they draw up to 14,400 Watts. At 220 Volts that would be a 65 Amp circuit in Europe or 60 Amps in the US with 240 volts. Using the Tesla Corded Mobile Connector they can draw up to 50 Amps in the US at 240 volts which is 12,000 watts. Ohms Law In Europe at 220 volts that would require at least 55 Amps.

Since I have an engineering background I do understand electrical circuits. Are you doing something different than I am aware of, ie. a different Wall Connector, etc.? In England you have the incoming 220 volt and the return neutral and you have Single Pole RCDs that energized just the hot side and and you have Double Pole RCDs that energize both the hot and the neutral. What am I missing? How are you getting away with a lower amperage RCD, what we commonly call a circuit breaker in the US. Are you simply using a lower power connector for the Tesla?

 

[MadScientist]

Most single phase, home chargers are rated at 7kW in the UK

 

[Jeeves]

What type of circuit breaker tripped - over current or RCD etc?

I’m sorry to appear so I’ll informed, but I have no idea. It’s just those little switches on the consumer unit. Are there different types?

 

[Generator]

If you are using a Tesla Wall Connectors, they draw up to 14,400 Watts. At 220 Volts that would be a 65 Amp circuit in Europe or 60 Amps in the US with 240 volts. Using the Tesla Corded Mobile Connector they can draw up to 50 Amps in the US at 240 volts which is 12,000 watts. Ohms Law In Europe at 220 volts that would require at least 55 Amps.

Since I have an engineering background I do understand electrical circuits. Are you doing something different than I am aware of, ie. a different Wall Connector, etc.? In England you have the incoming 220 volt and the return neutral and you have Single Pole RCDs that energized just the hot side and and you have Double Pole RCDs that energize both the hot and the neutral. What am I missing? How are you getting away with a lower amperage RCD, what we commonly call a circuit breaker in the US. Are you simply using a lower power connector for the Tesla?

TWC in the UK is limited to 32A. No option for the 40A and higher outputs you get in the US. In fact 16A and 32A chargers are your only options here.

For single phase operation (220V) we tend to use a double pole RCD to look after earth leakage detection duties, and a single pole MCB to take care of over current protection.

3 Phase supplies are very uncommon in residential properties here, but if you do have 3 phase you can wire the TWC to accept 32A per phase (22kW).

 

[Generator]

I’m sorry to appear so I’ll informed, but I have no idea. It’s just those little switches on the consumer unit. Are there different types?

There certainly are. Different current ratings, as well as different response characteristics. For the most part though were only worried about the number, which represents the current rating.

 

[Jeeves]

There certainly are. Different current ratings, as well as different response characteristics. For the most part though were only worried about the number, which represents the current rating.

RIghto, thanks. I shall take a closer look tomorrow.

 

[NewbieT]

In the UK, single phase 230 volts -6%, +10%, so anywhere between 216v and 253v

 

[LukeUK]

If you are using a Tesla Wall Connectors, they draw up to 14,400 Watts. At 220 Volts that would be a 65 Amp circuit in Europe or 60 Amps in the US with 240 volts. Using the Tesla Corded Mobile Connector they can draw up to 50 Amps in the US at 240 volts which is 12,000 watts. Ohms Law In Europe at 220 volts that would require at least 55 Amps.

Since I have an engineering background I do understand electrical circuits. Are you doing something different than I am aware of, ie. a different Wall Connector, etc.? In England you have the incoming 220 volt and the return neutral and you have Single Pole RCDs that energized just the hot side and and you have Double Pole RCDs that energize both the hot and the neutral. What am I missing? How are you getting away with a lower amperage RCD, what we commonly call a circuit breaker in the US. Are you simply using a lower power connector for the Tesla?

UK supply is nominally 230 V phase to neutral, though its actually 240 V, the joy of harmonisation - the tolerances were set so the voltage didn't have to. An RCD (residual current device) and MCB (Miniature Circuit Breaker) are different things, an RCBO or RCCB is the combination of the two.

In round figures, 32 A at 230 V results in a 7 kW practical limit for single phase chargers. 3 phase 32 A chargers are capable of 22 kW, but model 3 AC chargers are rated at 11 kW (16 A), so they're a bit of a waste.

 

[MikeHolliday]

tend to use a double pole RCD to look after earth leakage d

I am very familiar with the RCD both single and double pole. Our Earth Leakage Detection is called GFCI (Ground Fault Circuit Interrupt). The Tesla Wall Connector actually has a GFCI built into it and about 90% of all new circuit breakers in new construction or new circuits installed in the US must be either be GFCIs or GFCIs with AFCI (Arch Fault Circuit Interrupters). Arch Fault Circuit Interrupters are looking for current draws where a wire maybe loose, frayed or similar issue which could could cause a fire and interrupts the circuit before a fire would start.

I do not understand why they would limit you to 32 Amps. But if you are limited to a 32 Amp charge then you need a breaker greater than 40 Amps. You could get away with a 40 Amp breaker, 32 Amps/.80 = 40 Amps, but when you have an electrical potential that is a constant current draw your breaker should be 25% greater than the maximum current draw. This is due to the fact that as the wire warms up the resistance increases causing a greater current draw. This is especially prone to happen in hot climates or in a situation where the wire does not geta good air flow to allow cooling.

 

[ringi]

, but when you have an electrical potential that is a constant current draw your breaker should be 25%

Not in the UK.

 

[MrBadger]

I’m sorry to appear so I’ll informed, but I have no idea. It’s just those little switches on the consumer unit. Are there different types?

If its over current/short circuit protection then there is normally just a little toggle switch typically on one of many MCB's.

That is different situation to a fault where a part of the circuit gets broken/disconnected and the current starts flowing via earth. In fixed wiring, that is handled by an RCD which will typically protect multiple circuits, or an RCBO, which combines RCD with over current into a single unit which typically protects a single circuit. A typical feature of RCD type breakers is a Test button.

So its useful to know what type of circuit breaker tripped as depending on what trips and why, you are looking at potentially over current, short circuit, circuit fault or ...

Unfortunately, RCD's can also nuisance trip as they work by allowing a certain amount of current to flow to earth under normal circumstances (typically 30mA) but the RCD may be over sensitive and trip at <30mA or, there can be an accumulation of little earth leaks (such as from normal power supplies) which can build up to more than the RCD rating either as a constant draw, or a brief transient moment, such as something on the circuit changing state; such as the car starting or stopping charge. This is one of the reasons why it is better to have the EV charging circuit on its own dedicated MCB/RCD that is not part of the main house fuse box. It is also why it is not uncommon for a UMC to cause a house RCD to trip.

 

[Jeeves]

Thank you all for your helpful replies. Regrettably, I don’t understand anything about electricity and comprehend little of what you have written. The installer put in a separate fuse box for the charger next to the original one for the rest of the house. Here is a picture.

The little switch labelled ‘CAR CHARGER’ is the one that tripped. Will this help you explain what happened to me?

 

[MrBadger]

Thats an MCB (over current or short circuit) rated at 40A. A 32A/7.2kW AC charger is maximum over here, so your MCB 40A fuse is slightly over specified which is fine if the cable is sized correctly.

Looks like you either had a short circuit (pretty much instant blow somewhere), the car drew substantially more than the 32A it should be drawing (potential risk of fire), your MCB is faulty or you are running another load on the same circuit as the 'CAR CHARGER' circuit.

I would get the electrician back to look at the electrical and EO side of things and if they do not find anything, contact Tesla. You may have a fault that the electrician/EO can diagnose, or for some reason, the car briefly pulled a very high current or caused a short circuit which is one for Tesla.

Either way, an MCB tripping should not happen. I would also leave the car charger MCB turned off (lever down) until it is looked at.

For future reference, the RCD is the double unit on the right with the yellow test button. May also be worth testing by pressing the RCD button and leaving off until sorted if you don't have anything connected to the left most circuit.

 

[Jeeves]

Thank you @VanillaAir_UK. There is nothing else on the ‘CAR CHARGER’ circuit.

I’ll get the installation company to check it out as you suggest. I did just flip it up yesterday and it charged fine again yesterday.

 

[MaDProFF]

Thunder Storm somewhere?
I had a trip that used to sometimes trip sometimes in my garage, in the end after many months we found it was a faulty trip