Stange fault on new installation

[Simlec]

Originally Posted by Simlec
Not sure where you are going with the old stuff, but most older TT installations have double pole rcd's or more than one CU. I'm trying to go to the place where you understand that the requirement for double pole isolation does not equate to a requirement for double pole protective devices. I haven't said that protective devices need to be double pole on TT. But they must be DP if used as isolators which they would be in this installation.
The problem is the op has designed/upgraded this install with single pole devices where they should be double pole.
Again there is no requirement for double pole protective devices. Again no but when used as isolators.
The whole design is a dogs dinner but he should be putting that part to current standards at least.
Yes there are problems with the installation, but as far as I am aware it complies with the requirements of BS7671! Again you can't use SP RCBO to isolate a circuit in TT system.

 

[Deleted member 26818]

No you can't use a single pole RCBO for isolation, that's why you use the double pole Main switch.

 

[suffolkspark]

Problem solved. It was indeed an accumulation of earth leakage.
Biggest culprit being the heatmiser underfloor heating system. I have 3 manifold sets and a UH1 at each this circuit alone was leaking 9mA!
Induction hob and ovens again were bad appliances as somebody mentioned.

System in now TN-C-S. 100A main switch at origin in 2 way ccu. There is now an MCB on the submain, which runs for 400mm from origin into the floor trunking at a depth of 100mm+. It then reappears at the main house consumer unit where it travels 1400mm straight up in a stud wall to the consumer unit. I have exposed the cable and fitted 2x2 earther metal trunking to provide the mechanical protection to this as i could not guarantee it would be at a depth of >50mm from the surface. The board is now configured as dual rcd and i have split lighting and power accross and spread the problematic circuits 50/50. I have a combined earth leakage of 39mA and everything is running perfectly! have some pictures if anybody is interested allthough nothing too exciting.

Thanks to those who offered constructive assistance

 

[Barrie Patrick]

Whats IMHO mean?

 

[GMES]

IMHO= In my honest opinion.

 

[richy3333]

Problem solved. It was indeed an accumulation of earth leakage.
Biggest culprit being the heatmiser underfloor heating system. I have 3 manifold sets and a UH1 at each this circuit alone was leaking 9mA!
Induction hob and ovens again were bad appliances as somebody mentioned.

System in now TN-C-S. 100A main switch at origin in 2 way ccu. There is now an MCB on the submain, which runs for 400mm from origin into the floor trunking at a depth of 100mm+. It then reappears at the main house consumer unit where it travels 1400mm straight up in a stud wall to the consumer unit. I have exposed the cable and fitted 2x2 earther metal trunking to provide the mechanical protection to this as i could not guarantee it would be at a depth of >50mm from the surface. The board is now configured as dual rcd and i have split lighting and power accross and spread the problematic circuits 50/50. I have a combined earth leakage of 39mA and everything is running perfectly! have some pictures if anybody is interested allthough nothing too exciting.

Thanks to those who offered constructive assistance

Who paid for the work, you or the customer?

 

[Risteard]

IMHO= In my honest opinion.

Or humble even!

 

[Octopus]

Or humble even!

I mean "humble"

 

[GMES]

Humble honest whats it matter between friends jmo