tt systems

[dippers]

Hi all,just started using this forum,amazed theres so many people on it.

I have to change a board on a TT system(haven't done one before).
The cpc looks to be around 6mm(not sure untill i test it wether to change it to a 16mm),and has an old rccb protecting a wylex db.

Can I use a 17th dual rcd board or do I have to use a normal board with rcbo's?
Also am I right in saying that the Ze has to be below 200 ohms and the Zs for each circuit 1667 ohms.

Appreciate any advice

Thanks All

 

[Dan]

Hello dippers, welcome aboard. Enjoy the forum.

 

[diditrain]

My advice is dont do it, which circuit are you wanting to change your cpc on?

 

[Guest123]

Welcome along.

As this is the introductions thread, try posting your querey in the relevant section of the forum.

You will get more views and replies there.

 

[rich.250]

Do you mean the main earth looks to be 6mm??
If so and it is not burried in the ground it is probably ok. 16mm if burried.

Yes you should aim for your Ze or rod Ra to be as low as poss.
Although the regs state that for a 30mA Rcd the max is 1667.

You could fit either db, I would be tempted to replace the main switch in either with a 100mA type s Rcd. (Time delay) for extra protection. Not required.
Personally rcbos is a better job but a lot more money.

Hope this helps

 

[rich.250]

And welcome dippers

 

[Sintra]

Hi & welcome.

 

[li150pacemaker]

Hi, welcome to the forum.

 

[CRAGS]

Hi and welcome

 

[MarkieSparkie]

Hi, welcome to the forum.