Main earth

[Andy B]

I`m rewiring 2 houses next door to each other for a customer. The existing installation in one house appears to be slightly newer than the other. The main earth in one house is a tt system whilst the other is tnc-s. Can I connect into the main head and turn the tt earth into a tnc-s?

 

[jibjob]

Assuming that the incoming supply cable was suitable for TNC-S/PME that would mean breaking the seals. Speak to DNO & get them to have a look. If you have a good Ra on you're earth rod it may not even be worth the hassle. Stick with the TT.

 

[Engineer54]

I`m rewiring 2 houses next door to each other for a customer. The existing installation in one house appears to be slightly newer than the other. The main earth in one house is a tt system whilst the other is tnc-s. Can I connect into the main head and turn the tt earth into a tnc-s?

In a word ...NO!!

Obviously there is a PME connection available from the DNO, so contact them and get them to convert to PME!! You can leave the TT earth in place by the way, especially if it has a good Ra value....