RCD Protection and Earthing Requirements

[flyingsparks]

Hi Everyone. I have been asked to change an old Wylex fuse board with a more 'up-to-date' consumer unit. It is in a farm building however it is under good cover (ie. no rain etc can get to it.) I was wondering a couple of things:

1. If there is no seperate earth (like a 6mm etc) coming across with the supply T+E cable should I turn this into a TT system and put in an earth stake and RCD?

2. If I dont need to make it into a TT system, is it advisable to have the RCD only protecting the sockets, as I am unsure how reliable the old wiring is, and dont want to find I cant keep the RCD in?

3. If I protect the whole board (only about 3 ways (1 lighting circuit and 2 socket circuits)) with an RCD should I use a 80/100A 30mA or a 80/100A 100mA RCD.

Thanks in advance for your help!!
Chris

 

[kai]

Use a 30MA RCD, because sockets need 30MA rating, especially if they are likely to be used to supply outdoor equipment , as is the case here.

 

[kai]

Use a 30MA RCD, because sockets need 30MA rating, especially if they are likely to be used to supply outdoor equipment , as is the case here.

 

[ban-all-sheds]

Frankly I'm horrified at the lack of knowledge you display by asking these questions.

Does the person paying you for your professional services know that you don't know what you're doing, and are having to ask advice on a DIY site?

Why aren't you aware of all the wiring regulations which apply specifically to agricultural premises?

And as for this:

2. If I dont need to make it into a TT system, is it advisable to have the RCD only protecting the sockets, as I am unsure how reliable the old wiring is, and dont want to find I cant keep the RCD in?

So you don't plan to inspect, and test, the existing wiring before replacing the CU?

You need to go back to college.

Or change your line of work.