Why are Mode 2 chargers not required to have O-PEN protection?
Why are Mode 2 chargers not required to have O-PEN protection?
Because they can be installed with a TT or TNS earthing system, but if you want to install them to a TN-C-S earthing system you are going to want the O-PEN protection.
Edit- I replied whilst eating a cheese sandwich in a lay-by alongside the North Devon Expressway before getting onto the M5, as you do.
I am sure that the manufacturers will tell you that Granny Leads can be used quite safely with TT and TNS earthing systems, as well as indoors with TN-C-S earthing, therefore they are fit for purpose when used appropriately.
But as a knowledgeable person you are going to want O-PEN protection if using the Granny Charger outdoors with TN-C-S earthing, but if you are going to fit that in a fixed installation you may as well go the whole hog and fit a 7 kW EVSE unit with the O-PEN built in rather than use a Granny Lead.
Mode 2 is a cable with an RCD in the ICCB and a standard plug on the end, not a fixed Charger. so they can be plugged into any standard socket.
True.
Appliance not part of the fixed installation, so the earthing arrangement is completely unknown, because they could be plugged into any available socket.
However according to the Wiring Regulations they should only be plugged into a socket that is marked as being suitable, so if an electrician installs a dedicated 13-amp socket that is marked as being suitable for EV charging, is it permissible to connect it to a TN-C-S earthing system?
A few weeks ago I had a conversation with a guy who knows about these things.
I said that one of my neighbours wants a socket on the front of his house for cleaning his car with a vacuum and pressure washer, obviously it could be used for a Mode 2 charging lead aka a Granny Charger, so what precautions are required as the house has a TN-C-S earth.
The advice I received was to just get on and do the job, because really it’s just another socket and if it wasn’t there another one would be used anyway.
I have not actually done the job yet as I keep getting involved in other things.
Granny leads are “cheap” and built on a budget, their use should not be encouraged. The manufacturers of them aren’t going to spec them up as they will not be competitively priced.
Granny leads are okay if:
The issue is when the vehicle is charged outdoors and the earthing system is TN-C-S, the answer to the issue is probably that Granny Leads should come with a health warning.
You can add to that list, a Granny Charger is safe if no one touches the vehicle whilst it is connected to the charging lead.
Around forty five years ago a lorry driver working for our local aggregate merchant was burnt and lost an eye connecting jump leads to a lorry battery.
He could not start the lorry so fetched a battery out of the workshop that had been charging overnight, put the leads on the spare battery then leant under the lorry bed and connected the lorry battery.
As well as being flat the lorry battery it was assumed it was also partially frozen as it was the middle of the winter, the battery exploded with enough force to blow a hole in the steel bed of the tipping wagon, which I saw myself I also saw the burns the driver received and he lost an eye.
Ever since then I have always put the leads onto the flat battery first, then stood back and connected the fresh battery.
Granny leads really need a similar approach, plug the lead into the vehicle to be charged then stand back and plug the lead into the wall socket, then when charging is complete disconnect at the wall first.
But in reality people will touch the vehicle whilst it is charging.
That's a bit like disconnecting the earth side of a battery before "live" (could be pos or neg).
I have never heard of a frozen battery - what is the freezing point of reasonably strong sulphuric acid? Perhaps there was a duff cell?
It was a 3.5 ton tipping wagon with a steel bed, the battery did a proper job of blowing a hole in it on an exceptionally cold morning.
Apparently in the UK Renault have written a ban on Granny Lead Chargers into battery lease agreements, so unless you buy the batteries they should not be used and obviously if you own the batteries it’s at your own risk.
In Australia and New Zealand Renault went further and said Granny Leads should not be used at all.
I have sent you a private message through the forum, I realised I have done electrical work for one of your bosses and I was a shareholder of the group of companies until three weeks ago.
My replies above are rather disjointed, but hopefully you can make some sense out of them.
People will buy Granny Leads because they see them as a cheap and easy solution.
Car manufacturers, electricians along those who write the legislation and guidance will strongly advise against using them.
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