service head 3 fuses

[soulman]

Hi, went to price for installation of a shower today. I needed to install a shower ccu by splitting tails in henly's block. The service head had 3 fuses and 3 cables one coming in from the left hand side and two going straight down. As i have never seen a setup like this and i couldn't see which fuse was feeding there installation. I told the customer they would have to phone there electricity supplier to install an isolator. They phoned them while i was there, the call was answered within a few minutes, the customer was then on hold and passed around as nobody knew what an isolator was (southern electric). eventually after 45 minutes a very nice lady came on the telephone and asked to speak to the electrician i told her exactly what was required. She replied by saying as long as i had the correct qualifications i was free to pull the fuse and reseal myself as they no longer fit isolators. I explained that the service head had 3 fuses & i was unsure whether the other two fuses were feeding the next door properties. She said i would have to ring the local electricity board, and gave me a number for n power. I haven't rang as yet. I have spoken to two electricians today who have both said there will be no fuses in two of them and its normally the one on the left hand side that feeds the property. as i didn't want to be pulling fuses if they were feeding next door especially if they were under load. I only hung around when the customer was on the telephone to see how much of a hassel it is to get an isolator installed. i still haven't decided what i'm going to do about this one yet. But one thing i'm sure about is i will never ring anybody to pull a fuse. i will assess the service head and fuse, make sure the load is off, snip the seals pull the fuse & reseal afterwards. i was told by a meter fitter when i was training, to just pull the fuse anyway. I am also going to buy myself a face mask and 1000v gloves & pump. i'll just keep them in the van and use when needed.

I think this fuse pulling is one of the most difficult, unclear aspects of being an electrician.

If anyone has any advice on the service head with 3 fuses (tns) it would be appreciated.

 

[electrician786]

Could you not trace the cable from the top of the service fuse to the meter?

 

[Badger]

can you upload a picture of the setup so we have an idea of whats going where if you know what i mean.

 

[soulman]

sorry didn't take a pic. no i couldn't trace the fuse as the line & neutral tails come out of the head to the left hand side and it was all enclosed.

 

[Sharpend]

Put a clamp meter around the tails one at a time with the property you are working in main switch in cu switched to off position therefore no load. Make a note of the readings. Then turn on main switch with a set load say kettle only take readings again. Compare the amps to that of the kettle and unless you are seriously unlucky you gave now determined which is yours.

 

[soulman]

never thought about a clamp meter, thought they only work with line & neutral seperate

 

[batty]

Are you sure it not just a three phase head with only one phase being used what sort of property is it?

 

[soulman]

i have seen that before 3 phase head with only fuse being utilised, but this head had 3 cables one on the right which looked like it was going into the head and two directly below the two fuses to the left

 

[Evans Electric]

That sounds like they jointed three of their feeders at that position . I've seen two cables before, one in and a short loop feed to next door but not fused in that property.

As said , I 'd guess that two of the fuses do nothing . They've just used a 3 phase cut out for jointing through.

If the neighbours are not on life support machines I'd pull them one at a time till it goes off, seeing as you were given permission. There should not be fuses in that house feeding other properties.

 

[ProDave]

Like others I'm dying to see a picture of this.

So where is this, you mention SSE and N power. Are SSE the DNO and N-power the energy supplier. My experience is N-Power know nothing, but SSE are helpful, and as you have been told, they are happy for qualified people to pull their fuses.

I'm struggling to understand why you can't trace the wires from the CU, is it some distance away? but as already suggested use your clamp meter, then once you have found the right fuse, pull it, you have already been given permission from SSE to do so (assuming you are qualified)

 

[kerching]

Surely it is the tails that you want to trace and not the supply cable? or am I missing something, hard to tell from the description.

It could be a 3 phase service

It could be a 3 phase head with only one fuse connected

It could be a back to back service with the fuse on 'your' side

It could be an old DC service head [thought they had all gone now, they have around here]

Without pics we are like a bunch of Archaeologists!............a group of people guessing?!?!?................ :coat

 

[soulman]

cheers. i will get a photo this week. the tails from the fuse come out of the service head and its all enclosed so you cannot see which fuse is feeding the tails, all the 3 phase service heads i've seen you easily identify what fuse feeds what. the supplier is southern electric who were more than helpful. n power i presume are the dno. i very much doubt after thinking about it, if there are any fuses in two of them. but i still wish to be cautious i had a small belt a couple of weeks ago when taking a zs reading from a light and i dont intend to get one again. (i touched one of the probes when a plumber nudged me).

 

[Andy™]

come accross stuff like that often

also, some of the fuses are wired to other outgoing cable internally, so even though there is no cable leaving the head at the top of the fuse doesnt mean that the fuse isnt in use. sometimes this fuse may be a solid link

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I think this fuse pulling is one of the most difficult, unclear aspects of being an electrician.

couldnt really be any more clear: you are not allowed to remove the fuse without permission of DNO. which NEDL do not allow you to do

 

[soulman]

Andy i see your from south tyneside, so who do you contact when the fuse needs pulled or an isolator needs fitting & is it a straight forward procedure.

Cheers

 

[Evans Electric]

Don't ask!!

 

[PC Electrics]

Write out 100 lines:

"next time I will take a picture or three"

Every phone has a camera now - always think "pictures"

 

[ProDave]

Ah, so SSE are the energy supplier, NOT the DNO.

So do they actually have the right to give you permission to pull the fuse? after all, it's not theirs.

SSE are one of the most forward looking DNO's and do give permission for qualified people to pull their fuses where they are the DNO. I'm just not certain in this case if they are not the DNO that they actually have authority to do so.