TT to PME Head Earth Terminal

[bozobro0]

Why is it that when the DNO provide an earth at the head they fit a cover over the terminals that you cant get off unless you remove the cutout and cut the seals.Why cant they provide an earth block at the side of the head if you not supposed to access their terminal.They have supplied alot of premises around here over the years with PME. Most are still on a TT system,and alot of them have damaged or non existent cable to the rods.:frown2:

 

[DurhamSparky]

cause they want the cash to install earth!!

 

[bozobro0]

Think ill pin a fiver next to the cutout and call them out then,that should easily cover the price of 1 meter of 16mm earth.

 

[DurhamSparky]

how do you know the TT is actually PME!! there are PME Heads around my area that are actually still TT as they had no standard heads on van / shelf!

 

[Dunc]

how do you know the TT is actually PME!! there are PME Heads around my area that are actually still TT as they had no standard heads on van / shelf!

They put a green PME sticker on it. No sticker = no PME as far as i understand.

 

[bozobro0]

They stick a PME label on the board by the head.And when they run the new supply cables in you notice that on certain poles there is a cable running down,or from the outside joints on peoples houses to earth.

 

[DurhamSparky]

They put a green PME sticker on it. No sticker = no PME as far as i understand.

would not pay any attention to stickers on DNO cut outs...! round my way its still a £5 fine if you tamper with the equipment!

 

[bozobro0]

Have you heard of anyone being fined/prosecuted for cutting the seals????

 

[Dunc]

would not pay any attention to stickers on DNO cut outs...! round my way its still a £5 fine if you tamper with the equipment!

Are you saying the DNO is not a trust worthy organisation?! A check at the pole is a good shout too. If you want to get access to the terminal without cutting seals a 6mm drill bit and a steady hand will solve the problem.

 

[Geordie Spark]

cause they want the cash to install earth!!

Yep ....... £130 something + VAT :death:

 

[mechelec]

First of all the DNO wont stick a PME label on a new cutout if it is not PME (usually) If you want to use the supplied PME earthing terminal hopefully the following will help from a previous post of mine.
Is the cutout is a modern grey series 7 with a cover on the side for the neutral terminals and earth? if so there are some drill out points on that cover for access to the 3mm grub screws to enable you to knock out the hole in the top to insert your 16mm earth all without removing any seals. BUT before you do this do a loop test between the neutral and phase of the incoming supply with main switch off. If it is below 0.35 ohms you can assume it is OK to PME and insert your earth. This is all the DNO will do if they come round. Be very careful if you are unsure what should be drilled out, leave it well alone and get the DNO in. ( I accept no responsibility if you drill/knockout the wrong part)
I did get chastised for posting this before but it is usefull info for the educated

 

[bozobro0]

Good info mechelec,after all these years i never realised that front cover had drill out points,just had a look at the one in my house,and yes your correct.

 

[mechelec]

When the DNO fit a new cutout that has a PME earth available to the customer they should drill them out for you. Unfortunatly most dont bother drilling them out.They wont connect the customer earth as the installation has to comply with the 17th edition regs re bonding etc. and the DNOs dont test anymore. At one time they had their own testers who would test the installation before connecting their supply.

 

[IQ Electrical]

First of all the DNO wont stick a PME label on a new cutout if it is not PME (usually) If you want to use the supplied PME earthing terminal hopefully the following will help from a previous post of mine.
Is the cutout is a modern grey series 7 with a cover on the side for the neutral terminals and earth? if so there are some drill out points on that cover for access to the 3mm grub screws to enable you to knock out the hole in the top to insert your 16mm earth all without removing any seals. BUT before you do this do a loop test between the neutral and phase of the incoming supply with main switch off. If it is below 0.35 ohms you can assume it is OK to PME and insert your earth. This is all the DNO will do if they come round. Be very careful if you are unsure what should be drilled out, leave it well alone and get the DNO in. ( I accept no responsibility if you drill/knockout the wrong part)
I did get chastised for posting this before but it is usefull info for the educated

I'm not chastising anyone but I will say that a neutral loop impedance reading of below 0.35 Ohms is not an indication that PME provisions are installed on the network, many TN-S systems will meet this value but won't have any multiple earthing installed!

It's a gamble that's not worth the risk to me, you're altering the means of earthing for a start which is notifiable under Document P so there now exists a record of your involvement, also backed up by any invoice issued.

Is it just me here or is everyone doing a quick neutral impedance test then forming their own PME?

 

[bozobro0]

No,I would only connect to head terminal if there was a PME label on the board.I think some confusion comes into it when as mentioned in a previous post,when the DNO have fitted a PME type head as that's all they had on their van,but no label=no PME.