no incoming earth on the supply cable,been told to put an earth electrode in.

[johnhainsby]

hi there i went to a job the other day,and found there was no incoming earth on the main supply cable,i was told by the supply company,to install an earth electrode,the incoming supply system is a t.n.s.type,would this electrode then make this a t.t. system,if so would i have to upgrade the exsisting consumer unit,with an insulated type with r.c.b.o. devices,with a standard 100 amp main-switch.?:nonod:

 

[telectrix]

if it's TNS then you should have a connection on the lead sheath of the supply cable. if not, fit a rod. if the CU is insulated, then a 100A main switch, + RCD/RCBO on all circuits, as you rely on the RCD for fault protection.

 

[sparks_114]

Yes you would effectively have made it into a TT system. If you're planning on leaving it as a TT then you will need to install RCBOs. I am not sure if you would leave the existing CU (be it split board or else) in the short term as an earth stake is an emergency procedure in the event of no earth being found and I am not sure one can also dive in for a CU change instantaneously in such an emergency situation. Hope this helps. Cheers

 

[johnboy6083]

in a TT system, it is very very unlikely that you will acheive a stable Ra anywhere near good enough to allow enough fault current to flow, in order to trip your MCB's. this is why RCD's are used.
Bear in mind that the only decent way to acheive discrimination with RCD's is to use S types.
Like you have already suggested, RCBO's are the best way to go.

with your rod, try and achieve a low reading. knock more than one rod it, as increasing the rods length is the best way to lower your Za. if you hit rock say 3m down, then install other rods in paralell with this.
i have to agree with Engineer 54 on this subject, we always install belt and braces (flyleads on boxes, CPC in conduit and trunking ect), however most sparks dont seem to try with TT systems.

 

[Deleted member 26818]

Yes it would then make the installation TT.
Confirm first, that the supply company won't instal an up front RCD in an insulated enclosure, or convert to TN-C-S.

 

[SirKit Breaker]

Why not just apply for a PME connection?. Cost in YEDL area is about £160 and is usually done in about 4 weeks.

Cheers..........Howard

 

[telectrix]

Doesn`t the supply company now have a responsibility to provide an adiquate means of earthing at the service head? After all the cutout is their property......If so then a tn-c-s is the way.....

afaik, they have a duty to maintain any earthing arrangement they have supplied, but don't think they are obliged to fit one.

 

[Engineer54]

The DNO shouldn't be charging anything if the supply is already derived from a PME'd TN-S supply. They are, are they not obliged to maintain a supplied earthing means.

I would kick up a fuss, and remind them of there statuary obligations... But knowing the DNOs these day's they will have some small print get-out clause!!

 

[telectrix]

The DNO shouldn't be charging anything if the supply is already derived from a PME'd TN-S supply. They are, are they not obliged to maintain a supplied earthing means.

I would kick up a fuss, and remind them of there statuary obligations... But knowing the DNOs these day's they will have some small print get-out clause!!

clause usually ends with ******* at customer's expense.. ke-ching

 

[Geordie Spark]

clause usually ends with ******* at customer's expense.. ke-ching

Yes it does.

NEDL wanted £130 something + VAT recently.

(they didn't get it though !! )

 

[ezzzekiel]

bit pointless even if they will upgrade and you have to wait a few weeks then you couldnt leave it without an earth so you will put a rod in anyways

 

[johnhainsby]

Hi there thank's for all the replies posted,i did get in touch with the local supply company,and they said it would cost about £290 plus vat,to supply the premisus with a main earth connection to there main incoming cable,but first they would need to send an engineer to survey the job first,and then they would send me a written estimate,i would then have to pay for the job first before they could process the job .

 

[Engineer54]

As i said before, they are duty bound to maintain an existing supplied earth connection, So WHY should you or anyone else pay, to carry out there responsibilities???

The supply in the street must already have been PME'd, and it's the same cable that's always been there supplying your installation with an earth connection, ...Right?? So why would you pay 290 quid for a strap between the cut-out neutral connection and the MET??

 

[johnhainsby]

THIS PROBLEM WITH PROPERTY'S HAVING NO MAIN INCOMING EXTERNAL EARTH,STARTED IN OUR AREA,WHEN THEY STARTED REPLACING THE OLD INCOMING SUPPLY HEADS,WHICH WERE THE METAL TYPES,WITH NEW BAKERLITE TYPES,THE OLD METAL TYPES,ALWAY'S HAD A MAIN EARTH LEAD CONNECTED TO THE INCOMING MAIN CABLE,BUT THE NEW BAKERLITE TYPE SAT STRAIGHT ON TOP OF THE MAIN CABLE ,WHICH MEAN'T THERE WAS NO LEAD SHOWING WHERE YOU COULD FIT AN EARTH CLAMP,BUT I HAVE BEEN INFORMED NOW THAT THESE TYPES OF CLAMP'S ARE ILLEGAL BECAUSE THEY DAMAGE THE NETWORK CABLE,SO THE SUPPLY COMPANY LIKE TO SWEAT AN EARTH LEAD ONTO THE MAIN CABLE,OR USE A SPRING LOADED TYPE OF CLAMP.:rockon2::rockon2::rockon2:​

 

[alarm man]

john,tone down the caps and font size,its hurting my eyes..:1eye: