No earth in a consumer unit!

[boltonsparky]

I went to connect up a cooker today for an elderly couple.

I removed the consumer unit cover to carry out an r1 + r2 test on the cooker circuit and to my amazement found there was no main earth from the consumer unit to the MET!!!

The only cables in the earth terminal in the consumer unit were the cpc's.

I took a reading and got 0.14ohms between incoming live and the earth terminal in the consumer unit, so at least they had got an earth but obviously through another path and probably an insuficient one to take a big fault current.

I asked the customer when he'd had his consumer unit changed as it was a newish one, he told me it had been in for three years and was installed by an electrical contractor.

I immediatly installed a 16mm earth conductor.

I'm still amazed an electrician could be stupid enough to forget this or not have the concience to not install it deliberatly.

Just as I think Ive seen it all something else even worse crops up!!!

 

[Andy™]

whats the earthing arrangements? may have been a rod connected?

came accross similar a few times before. spark had left 16mm earth for DNO to connect once head was changed to PME. DNO didnt connect it.

 

[green-hornet]

Where there any certificates issued for the change, I would suspect it was not an electrician who carried out this work, no electrician would have forgot the first cable to connect to any electrical installation.

 

[boltonsparky]

whats the earthing arrangements? may have been a rod connected?came accross similar a few times before. spark had left 16mm earth for DNO to connect once head was changed to PME. DNO didnt connect it.

It was a TN-s system and had a 10mm bonding cable to the gas and water.

I suspect the earth was coming from the immersion heater cpc through the pipework back down to the MET via the bonding cable.

If this was the case the size of the earth at its smallest point would have been the cpc of the immersion heater cable... a 1.5mm cable!!!

 

[Andy™]

It was a TN-s system and had a 10mm bonding cable to the gas and water.I suspect the earth was coming from the immersion heater cpc through the pipework back down to the MET via the bonding cable.

If this was the case the size of the earth at its smallest point would have been the cpc of the immersion heater cable... a 1.5mm cable!!!

definitely not good!

 

[jl-heating]

typical i have seen a few were the 16mm is connected but coiled up behind the cu .. it never fails to amaze me .

 

[Evans Electric]

Bolt on , I'd guess the Ze was coming from the 10mm bond on the water /gas IMO.

We used to try to do things right some years ago by requesting a cut-out upgrade and earth terminal . Also remove our temporary Henley blocks and connect our new tails. We would find , on returning that they had done their bit but left our 16mm G/Y unconnected. After complaining we were told it was the contractor's job , although it must have been obvious that we had finished and unlikely to return.

 

[green-hornet]

May be worth noting that if you bond all back to an earth block so you only have the 16mm going up to the cu, the dno when finished are obliged to connet the earth to the main met. Has all your bonding is in place there is no need for a return visit.

I always book the visits and so know when they are comming, I like to be there if I can to check its done right.

 

[Andy™]

May be worth noting that if you bond all back to an earth block so you only have the 16mm going up to the cu, the dno when finished are obliged to connet the earth to the main met. Has all your bonding is in place there is no need for a return visit.I always book the visits and so know when they are comming, I like to be there if I can to check its done right.

is that so when the monkey arrives, you can check that he knows how to test polarity etc?! going by some installs, they cant even manage this!

 

[green-hornet]

is that so when the monkey arrives, you can check that he knows how to test polarity etc?! going by some installs, they cant even manage this!

I watched a young lad doing one such change and his mate said what are you doing?

I looked over his shoulder to find him connecting the live to the middle contact bar on the meter!

Simple mistake? I doubt it but they still make them, then call us for cutting seals.