Fixing TT earthing problems and gas bonding for an EV charger

[ericmark]

No bonding at all would be a C2

So any TT installation is a C2? I do remember my father-in-law getting a contractor to rip up and re-lay the floor in an operating theatre, as the wrong glue used, and the floor's bonding was compromised. Seems it needed a glue which could conduct to stop static build up.

Nearly every other electrical item used in one's garden is class II, it seems crazy why EV's are not class II, It seems all the rules are being rewritten in the push to have electric cars, anything else, caravans, boats etc, TN-C-S supplies are banned with good reason. And an AC supply has to be designed, so one can never get more than 50 volts to true ground. Instead of making them safe, they just change the rules.

 

[JohnW2]

So any TT installation is a C2?

It's fairly easy to argue that a TT installations does not need any main bonding, since it is almost always the case that the potential 'introduced' by an extraneous-c-p will be ('true') earth potential, which should be about the same potential as the earth electrode (hence MET) in a TT installation.

However, strictly speaking there is (per definition of extraneous-c-p), at least theoretically, a very slight chance that, in extremely unusual circumstances, an extraneous-c-p could introduce a potential other than (higher than) earth potential - so I suppose one can argue that main bonding is required?

And an AC supply has to be designed, so one can never get more than 50 volts to true ground. Instead of making them safe, they just change the rules.

One can't deny that a 50V maximum for 'touch voltage' is 'better than nothing' but, particularly for 'wet people', 50V can be plenty enough to result in a fatal shock.

 

[pete01]

So any TT installation is a C2?

I would bond extraneous parts on a TT system.

 

[JohnW2]

I would bond extraneous parts on a TT system.

I imagine that we all would (I certainly do in my TT installation) and it's certainly required for compliance with BS7671 (which makes no exception of TT installations).

 

[ericmark]

Sorry I intended to say IT. Yes need bonding with a TT.

 

[JohnW2]

Sorry I intended to say IT. Yes need bonding with a TT.

As I wrote, bonding is seemingly almost never going to be of any value in a TT installation, but it is 'required'.