Supply Upgrade

cosmarchy · Aug 18, 2010

Hi all,

I have an old house with an old supply which I want to upgrade. The house was built in 1903 and at some point a 30A supply was added which I want upgraded to 80A.

The incoming cable appears to be in a black fabric wrapping which I am informed is probably lead??????? The cable is connected to the main fuse and the earth is clamped around the outside.

I've phoned EDF who say they will come around to look at upgrading the fuse. What I want to know is whether, from peoples experiences, that they will replace the cable? Quite frankly I hope they do but will I have to ask them to do it or will they do it automatically?

Thanks

ezzzekiel · Aug 18, 2010

no, chances are they will just uprate fuse unless there is a fault on the cable it will be left as is

rick · Aug 18, 2010

In a similar situation the DNO said existing cable was OK up to 60A but luckily there where two phases available so installed second phase at 60A also. House in question was of similar age so might be worth seeing what the incoming cable is.

nickblake · Aug 18, 2010

The size of fuse being installed these days is 80 amps , to replace the cable would be a major job likes been said unless there is a fault even then they might just joint it rather than replace

Knobhead · Aug 19, 2010

Would be interesting to see the cable, what's the over all diameter. At that age it may be jute insulated concentric with lead sleeve from a early DC system.
The house I'm in at the moment was originally DC fed via a local balancer gen set feed from the tram supply. This house was built in the 30's

cosmarchy · Aug 19, 2010

I would try to get some photos but unfortunately I had to re-lay the wooden floor again so cannot easily get access at the moment - the fuse end is a little eassier.

From memory, and where it pokes throught he concrete into the fuse, the diameter is approx 25mm and looks like its been mummified with tarred linen...

They have said they'll come round and assess everything before upgrading the fuse but i'd be suprised if they don't replace it as I cannot believe the fuse and holder is capable of taking 80A, though I may be wrong. It's one of those 'old' black ones; not really sure how else to describe it!! I'll get some photos...

High Tower · Aug 19, 2010

Ok, to clear a few things up as i do have a little experience in this as i have witnessed a few being done, hopefully Kung will be about soon as if i remember correctly he used to work for a DNO

You need your main fuse uprating, however in most cases if the cut out is a bakalite variety it is not suitable for such a upgrade.

You will need a new henley style cut out installing with probably a 100a cut out as this seems to be what most of them install these days, and they normally provide a TNC-S earthing arrangement (possibly a PME) or if you are really unlucky they may refuse on one of the many BS excuses the dno have for not doing so.

So take into account if they will not provide a TNC-S then you will then be responsable for makin a TT arrangement, they will also fit a main Isolator to the install

However it is not possible to fit a henly service head to a tar and paper cable!

So, and this is the fun part and its great to watch them do it.

They will cat and genny the cable to find its route in relation to their plans, dig a bloody big hole on the property and expose approx 8-10 ft of the tar and paper cable, using a blow torch they will clean off the tar, circumcise the lead sheath, remove paper and expose the phase and neutral conductors.

Next out comes the volt stick and marigolds and the phase is identified, seperated by means of a plasic wedge between the two and cut live, capped and then the neutral is cut.

The old service head can now be smashed off the wall and old portion of tar and paper removed, new cut out installed and complimented with a new length of split con cable run as far as the trench, it will then be spliced with the cores of the tar and paper using brass couplers and waveform as a insulator, all done with marigolds and done live, then the joint is encased in a resin joint and resin poured to make a sound connection, tails installed to isolator and a measurment of Zs is taken, hole filled in.

It is then left for a competent person to connect the CU tails to isolator and deal with earthing arrangements

The chances are that the DNO will complete this upgrade free as its is their responsability to phase out the old style cutouts and E-on have certainly done the last few that i have done free for this exact reason.

If andyone is better informed than me on this please feel free to correct me as necissary!!

Hope it helps

cosmarchy · Aug 19, 2010

High Tower said:
You need your main fuse uprating, however in most cases if the cut out is a bakalite variety it is not suitable for such a upgrade.

Not sure what this ones made of

High Tower said:
However it is not possible to fit a henly service head to a tar and paper cable!

So, and this is the fun part and its great to watch them do it.

They will cat and genny the cable to find its route in relation to their plans, dig a bloody big hole on the property and expose approx 8-10 ft of the tar and paper cable, using a blow torch they will clean off the tar, circumcise the lead sheath, remove paper and expose the phase and neutral conductors.

Next out comes the volt stick and marigolds and the phase is identified, seperated by means of a plasic wedge between the two and cut live, capped and then the neutral is cut.

The old service head can now be smashed off the wall and old portion of tar and paper removed, new cut out installed and complimented with a new length of split con cable run as far as the trench, it will then be spliced with the cores of the tar and paper using brass couplers and waveform as a insulator, all done with marigolds and done live, then the joint is encased in a resin joint and resin poured to make a sound connection, tails installed to isolator and a measurment of Zs is taken, hole filled in.

man do I want to see this

High Tower said:
The chances are that the DNO will complete this upgrade free as its is their responsability to phase out the old style cutouts and E-on have certainly done the last few that i have done free for this exact reason.

I do hope so

Thanks everyone for your help so far, here are some pictures as promised.