My new bungalow looks like John Wayne wired it!

[Big Richy]

This is my first post so go easy on me or will find you and hurt you.

I have recently bought a 1930's bungalow and on checking the wiring it is lashed right up. It looks like it's had years of DIYers or lazy electricians. I'm in the process of a complete rewire. I have installed a new split load consumer unit bristling with RCD's. On closer inspection there are two main earth's (16mm). One was connected the other was not. I traced the earth which was not connected and it goes back to the meter and is bonded to the neutral. The Live and Neutral then go up to the overhead line so it looks like it was a TN-C-S system. I have traced the earth that is connected and it runs down the outside wall and under the patio. What is the best way to check if this earth is a TT (spiked) earth or if the board have ran it back to the pole? I would ask Western Power but I know I would get more sense out of my dog! If it is a TT system then should I connect it at the consumer unit to make a true TN-C-S system or should I bond it at the meter?

Cheers



Richy

 

[Darkwood]

Welcome to the forum

 

[Pete999]

Not going to form an opinion, I value my life.

 

[Big Richy]

Hi Pete,

I meant I would only hurt the condescending types I have seen on other forums. Being a bit long in the tooth we all went through that in our apprenticeships! Your feedback on my earthing dilema would be gratefully received. Besides Northampton would be a bit of a trek!

Cheers

Richy

 

[drzsta]

Have you done any testing since changing the CU?

 

[Big Richy]

No I haven't tested yet as I haven't finished wiring it. Getting the consumer unit up was just phase 1. I'm pretty sure I'll get a good reading off both earth's, I was just wondering if there was a quick way to check to see if the system is TT or TN-S to avoid having to hack out any walls when the plastering is done and the testing is done. It looks as though the earthing system was changed at some point but I can't be sure as the rest of the wiring was such a mess I don't want to mix up two earthing systems.

 

[Deleted member 9648]

Pictures would be useful

 

[Midwest]

Ohh dear, your profile says 'electrician', please expand.

 

[Darkwood]

A picture of the cutout would be good, its common for the old TT overheads to be converted to TNCS, the style of cutout would reveal this, it would seem the old systems rod has been left connected and possible through confusion a new supplied earth has been disconnected, it could also be that someone has dangerously strapped a TT neutral down to earth.

Can members at least wait until the OP has responded to questions before making judgemental comments, I know plenty of seasoned sparks out there who are good at their job and know the regs backwards but present them with a set-up or scenario new to them and they are and confused and search for answers.

 

[Midwest]

Can members at least wait until the OP has responded to questions before making judgemental comments, I know plenty of seasoned sparks out there who are good at their job and know the regs backwards but present them with a set-up or scenario new to them and they are and confused and search for answers.

Opening line didn't help though.

 

[7029 dave]

Hello Kevin. Spent some money.

 

[Flanders]

It is probley worth calling western power they came out to one of my jobs (no charge) to comfirm if the system was tnc or tncs it took about a week and was on hold for about 20mins but i did get a definitive answer rather than us second guessing.

 

[TJ Anderson]

This is my first post so go easy on me or will find you and hurt you.

I have recently bought a 1930's bungalow and on checking the wiring it is lashed right up. It looks like it's had years of DIYers or lazy electricians. I'm in the process of a complete rewire. I have installed a new split load consumer unit bristling with RCD's. On closer inspection there are two main earth's (16mm). One was connected the other was not. I traced the earth which was not connected and it goes back to the meter and is bonded to the neutral. The Live and Neutral then go up to the overhead line so it looks like it was a TN-C-S system. I have traced the earth that is connected and it runs down the outside wall and under the patio. What is the best way to check if this earth is a TT (spiked) earth or if the board have ran it back to the pole? I would ask Western Power but I know I would get more sense out of my dog! If it is a TT system then should I connect it at the consumer unit to make a true TN-C-S system or should I bond it at the meter?

Cheers



Richy

View attachment 32446

You really should to contact WPD to confirm the earthing and utilise the earth they provide. They will definately make sense and will come and check if required. If you want to go the TT route then I would suggest take a Ze on the earth that you suspect is a rod, if if gives a satisfactory reading then uncover it and make it accessible, if required then install a new rod. Also have you just put a new DB on the existing circuits?

 

[TJ Anderson]

No I haven't tested yet as I haven't finished wiring it. Getting the consumer unit up was just phase 1. I'm pretty sure I'll get a good reading off both earth's, I was just wondering if there was a quick way to check to see if the system is TT or TN-S to avoid having to hack out any walls when the plastering is done and the testing is done. It looks as though the earthing system was changed at some point but I can't be sure as the rest of the wiring was such a mess I don't want to mix up two earthing systems.

Richy, do you know what the expected Ze value ranges for TN-S and TT earthing arrangements? Your answer will help me understand how to answer you further.

 

[Big Richy]

Hi Darkwood,

Cheers for your advice. I will post some pictures on the weekend. The reason I'm unsure at the moment is due to the substandard work that has been carried out previously. I'm finding it difficult to get my head around what they were thinking at the time they done it and wanted a second opinion on the matter. We've all dropped a clanger at some point in our careers and I'm a belt and braces kind of guy myself and not too vane to ask.

Cheers

Richy