Warm Rcd?

[Jonperry64]

My first time charging. Using a granny charger. I read it should be used in conjunction with an rcd protector. After half an hour the rcd is warm. Is this as it should be or should I plug directly into the socket (which is cold)? According to the ismart app it is drawing 1.8kw.

 

[Tig170]

If thats all thats on the circuit, then no it shouldn't be warm, but of course if you've got the washer & dishwasher also running on that circuit, then it may get ever so slightly warm to touch, but nothing of any signifcance.

 

[siteguru]

I think @Jonperry64 means he has the granny plugged into a plug-in RCD (e.g. what you might use with a lawnmower), rather than the MCB in the consumer unit.

What is the RCD rated to? 1.8kW into the car is probably 2kW+ drawn through the RCD ... that's around 9A or so, continuous.

FWIW I usually just plug mine directly into a socket.

 

[Jonperry64]

It's the only thing on the circuit. It's supposedly rated for 3. 12kw (https://www.argos.co.uk/product/982...jXgJwl8h7daK4oFMOOoaAuz5EALw_wcB&gclsrc=aw.ds).

I think I'll plug it in direct. Cheers.

 

[hojnikb]

It's the only thing on the circuit. It's supposedly rated for 3. 12kw (https://www.argos.co.uk/product/982...jXgJwl8h7daK4oFMOOoaAuz5EALw_wcB&gclsrc=aw.ds).

I think I'll plug it in direct. Cheers.

Doesn't house wiring have some sort of master RCD, that convers everything? In that case i'd say you don't need an extra one.

 

[Jonperry64]

Doesn't house wiring have some sort of master RCD, that convers everything? In that case i'd say you don't need an extra one.

Yes it does.

Doesn't house wiring have some sort of master RCD, that convers everything? In that case i'd say you don't need an extra one.

Having said that it's protected by one of these... (see pic). Maybe that's not an rcd? There was once a storage heater connected to it and I installed a socket instead. If the wiring could handle a storage heater I'd have thought it would be OK for the charger?

 

[hojnikb]

Having said that it's protected by one of these... (see pic). Maybe that's not an rcd? There was once a storage heater connected to it and I installed a socket instead. If the wiring could handle a storage heater I'd have thought it would be OK for the charger?

These look like regular automatic fuses rather than RCD. An RCD will likely be before all the fuses and will have a two buttons (one for test, one for on/off).

Maybe check if you have something like that and if it's wired to the heater wiring. If that's the case, i'd say you don't need the plug type rcd you now use.

 

[siteguru]

Maybe show us a photo of the full consumer unit, as close as possible?

 

[Tig170]

It's the only thing on the circuit. It's supposedly rated for 3. 12kw (https://www.argos.co.uk/product/982...jXgJwl8h7daK4oFMOOoaAuz5EALw_wcB&gclsrc=aw.ds).

I think I'll plug it in direct. Cheers.

Thanks - I'm with you now, my own experience of doing something similar almost ended in disaster. Not quite an RCD plug, but a short extension lead, be very careful with granny chargers.

T

Post in thread 'Complete newbie seeking advice'

Mar 5, 2024

Thanks, I think I will feel better once I have my charger fitted at home, until then I’m going to do granny charger from 6pm to 7am with a faster charge at a charge point at the weekends ? hopefully that should keep me going.

Be very very careful with granny chargers, as 10 AMP (2.3 kW) isn't enough to blow the fuse, but can get the plug very hot (due to the UK 13 A fuse). This is what happened to mine in recent times (after only 1/2 hr of charging - luckily I was working in the same area and located the burning smell within 5 mins ) - yes it wasn't the MG charger as such, but an...

• Tig170

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[Martinonline]

The consumer unit is showing Miniature Circuit Breakers which protect the installation against over current. They look old and it is likely the consumer unit is old and there is no RCD unless added extra prior to the unit. (Don't know if it is allowed nowadays but was offered to me in the past.)

As was posted in response to @Tig170's original post the plug damage looks like the result of high resistance at the fuse, there appears no heating damage around the pins.

You cannot assume anything with hidden wiring so must get an electrician to check.

However, in respect of you original post I would suspect the plug-in RCD was not up to the job. Try without the RCD, check the plug to ensure bright pins and in use how warm it and the pins gets.

If the cable/charger you are using is undamaged then the risk of electrocution is low and you can do without the RCD. Note the need for high load fully unwound extension leads.

I and many others used granny chargers for a long time without problems.

 

[dsimpkins]

I have to use an extension lead if I use my granny charger. I use an extension lead designed for EV charging, and it has an inline RCD. When in use, plug gets slightly warm. I tried an ordinary extension lead originally and it got warmer than I would have liked within 15/20 minutes, so got an appropriate lead.

 

[Jonperry64]

Thank you all. You're right about the consumer unit. It is old and doesn't appear to have rcd protection. I bought an expensive extension lead which uses 2.5mm cable and is 40m long. It is fully unwound. Now I've removed the rcd adapter and plugged in directly to the socket it doesn't even seem to be warm. As suggested, I just checked the plug pins and they are still bright and not at all warm. I won't risk leaving it overnight though. Hopefully Octopus will pull their fingers out and install my Zappi soon! Thanks for the advice. Much appreciated.

 

[Everest]

What is that bit of flex coming from the 13A socket - not the supply, I hope?

BS1363 sockets should be EV rated for continual use over 8A.

But more alarming to me is this...

You're right about the consumer unit. It is old and doesn't appear to have rcd protection.

Please do yourself and family a favour and get a sparky in to upgrade the CU as soon as possible. Not having any RCD on your house circuits is highly dangerous.

 

[dsimpkins]

What is that bit of flex coming from the 13A socket - not the supply, I hope?

Looks more like a telephone or alarm cable to me. If that was the supply to the socket it would have melted within minutes.

 

[Everest]

There was once a storage heater connected to it and I installed a socket instead. If the wiring could handle a storage heater I'd have thought it would be OK for the charger?

Best not to guess. What size MCB and what size wire is on that circuit? Night storage heaters commonly use two or three 850W elements, so only have a load of 1.7kW or 2.55kW. Small ones may be one element and four is the max.

Don't assume the wiring, which likely dates from the 1960's to 1970's, will be adequate - unless it has been checked.

 

[Jonperry64]

Yes, although I can see it looks like it, that's not from the socket it's a cable to a WiFi router which happens to pass under the socket. To elaborate on the CU. The one in the picture is an off peak supply for storage heaters. There is also a modern cu with appropriate protection that supplies everything apart from the storage heaters. As a temporary measure I have wired a new 13amp socket to an outlet that previously supplied a storage heater. This socket is the only thing wired to the "dining room" breaker seen in the photo. I must admit the socket is an MK one but not rated for EV. Didn't know they existed but I will replace it with one. If you have a link to one that would be very helpful. Many thanks.