Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

3 pin plug charging cable [UMC] query

This site may earn commission on affiliate links.
Ref. VanillaAir_UK totally agree with you. It sounds therefore that the DC component could blind ALL the rcds in the house. This is the confusion about what the Regs are trying to fix. I have several good electrical engineers working with me and I still cannot get a straight answer on just this subject. The Tesla Gen2 does not do O-PEN bit but its still has several good safety features. It may detect >6mA DC leakage, and 10/16/32A doesn't alter the fact that most cars come with a three pin charger with all these apparent concerns (OP...my Zoe didn't and the Tesla charger worked fine @32A).
 
Another solution gathering traction, is an active O-PEN detector that monitors the (earth?) voltage and if it exceeds a certain amount, iirc 80v, cuts the supply and earth.
Most of these solutions monitor the L N voltage and cuts the connection to the charger if it falls outside of the permitted range rather than monitoring the earth to ensure it doesn't exceed 70 V
 
The regs are trying to address two main issues.

The O-PEN fault condition is where the protective earth common to most households is damaged and earth starts to float at potentially dangerous voltages. Within the house, if you touch another metallic object, tap etc, that will also be at the same float voltage because they are typically bonded. However, outside, what you touch is likely not to be at the same floating voltage, but at ground voltage, so the difference in voltage between what you touch and what the supply is grounded at could be dangerously high. The solution is to ground sockets of equipment used outdoors (or double insulate) at ground level and not via the house earth, ie metal ground rods. Another solution gathering traction, is an active O-PEN detector that monitors the (earth?) voltage and if it exceeds a certain amount, iirc 80v, cuts the supply and earth. Some EVSE/charge points will have an active device built in. Hence why the regulations is for where the equipment is to be used rather than where the supply is located. One thing to watch out for is that supplies that use ground rods (not sure about active solutions) must not be located where a user can come into contact with other metal objects within the house or an internal circuit.

The main DC issue is that DC leakage is that it can blind other RCD devices causing them to be ineffective. So you can have a fault elsewhere in the house that should have been made safe by an RCD tripping but isn't because the even small DC current is preventing the RCD from doing its job. The solution is a circuit that detects >6mA DC leakage and trips the circuit - such as a B type RCD, although many EVSE/charge points have their own circuit built in.
The so the d.c. current comes from the a.c. rectification circuits during charging. More googling required (or Duck Duck Go-ing)
 
Ok I've bought a B type rcd...
IMG_20210815_184629.jpg
 
Here’s some relevant reading:
 
Here’s some relevant reading:
I was looking for this post. Thanks.
 
Hi, I'm having a new Contactum Defender consumer unit fitted in my out building / garage.

I plan to have a 16A (blue) socket installed in my garage for occasional use with the Tesla supplied 3 pin charger.

Can someone point me in the direction of a suitable 16a Type B RCBO that will suit my new consumer unit please?

I've tried looking online - most "Type B" that come up seem to be B curve and not what I need, seems a stupid idea using the same letters for the type of RCBO and curve type!

Thanks
 
Can someone point me in the direction of a suitable 16a Type B RCBO that will suit my new consumer unit please?

I have yet to see an RCBO with Type B RCD. Unless things have changed, you will need to protect with a separate MCB and Type B RCD.

Something like this may work out as a good solution. But it doesn't handle the O-PEN issue.

 
So I decided to try it given a couple of people who'd commented have had previous success with non Teslas. Charged the Skoda Enyaq IV60 with no issues at all. 8mph at 2kW/10A

As I understand it, the current Gen 2 UMC is more standard than the previous Gen 1 which was non standard in configuration and therefor could damage non Tesla vehicles. I've not come across an instance of this happening to Gen 2 UMC, but its well documented the Gen 1 damaging non Tesla vehicles.
 
As I understand it, the current Gen 2 UMC is more standard than the previous Gen 1 which was non standard in configuration and therefor could damage non Tesla vehicles. I've not come across an instance of this happening to Gen 2 UMC, but its well documented the Gen 1 damaging non Tesla vehicles.
The Gen 1 supported 3 phase and in their wisdom Tesla stuck 32A single phase down 2 of the 3 phases at 16A I believe which confused the hell out of some cars and the on board chargers blew a fuse.
 
[...]The Tesla Gen2 does not do O-PEN bit but its still has several good safety features. It may detect >6mA DC leakage[...]
Hi! I'm really curious how do you know that Tesla's UMC Gen2 can detect >6mA DV leakage? I'm just about to install special socket in my garage which I am going to use just for charging Tesla Model 3. I am going to use Tesla UMC gen.2 (which was included) for that. So I have spent last 3 days looking for an answer if I do have to install RCD type B or RDC-BB? I am sure that Tesla Wall Connector can detect >6mA DC leakage (since it's manual says that) so in that case RCD type A would be enough. The only place about UMC gen.2 that it also has that kind of module is here - in your post. Could you please ensure me that Tesla UMC gen.2 can detect such a leakage? Do you have any source of that info?