Consumer Fuse Query

[Chris]

We are about to move house and one of the things that came up one the survey was the wiring was in a shocking state. We went round for another look today and sure enough it is.

On contacting the supplier, the advice I got was that they don't care if I pull the consumer fuse (to facilitate a re-wiring) but they'll need a cert. of conformity from a spark to replace the seals (fair enough).

However, the consumer fuse is not like one I've come across before.

A picture of the meter board can be found here:

anyone give any clues to the configuration?

All the consumer fuses I have seen have had a single seal. Also what is the black wire coming out of the top of the earth terminal likely to be?

I didn't post make a picture of the consumer unit available as I didn't want to scare anyone.

Chris.

[Owain]

"Chris" wrote | However, the consumer fuse is not like one I've come across before. | A picture of the meter board can be found here: |

| Can anyone give any clues to the configuration? | All the consumer fuses I have seen have had a single seal.

That's perfectly normal. The left 3 sealed compartments are the phases, for a 3-phase incomer. Only one (red) is used in this single phase installation, the one on the right (black) is the neutral.

| Also what is the black wire coming out of the top of the earth terminal | likely to be?

An earth to something...?

| I didn't post make a picture of the consumer unit available as I | didn't want to scare anyone.

Oh, please do!

Owain

[Bob Minchin]

You have a three phase supply with a single phase meter attached. Not a problem. Just pull the right hand fuse. The one in line with the red wire feeding the meter.

When you have re-wired just bung the fuse back in. The meter readers are the only ones to see it and they are often contracted out readers and won't be at all concerned if there is a seal missing. My board fuse was unsealed for years (1982 til 2001). When leccy board came to fit a new meter a couple of years ago I asked the chap to fit a seal which he did without a query.

Good Luck

Bob

[BigWallop]

The system head is a three phase looped supply. The black wire coming from the top is the neutral connection from the supply.

There are two separate systems connected from the consumer side of the meter, hence the grey double insulated cables heading off to the right of the picture and then the other red and black ones which go off to the left and then upward. Both are from the consumer side of the meter.

The meter is only connected to one consumer fuse on the right hand side of the three phase head and is only sealed by one tag, so this would be the one you'd pull out when you go ahead with your rewire.

The earthing bonds are provided into the bottom of the white box on the right hand side of the supply head and the main connections have be taken to the steel armour of the mains supply cables. The consumer side earth bonding is provided by the green/yellow cables coming the top terminals of the white box.

Any clearer ?

[Chris]

Thanks Bob. Will anyone be unduly upset if I remove the lower seal on the meter to replace the tails? (If required)

The consumer unit is a museum piece and the tails aren't well routed.

Also, i'm assuming that it's ok that the are a pair of tails from the meter. One (going off to the left) is the main CU and the off to right is a secondary CU (not sure for what yet, probably either an immersion or the garage). Would it be better to split this via a Henley block instead?

[Chris]

No, that's great thanks. Never encountered a three phase head before.

Thanks for the help.

[Bob Minchin]

I really dont think anyone will worry about missing seals.I remove all when I re-wired in1982. I shortened the overhead cable, moved the meter from the wall in the hall to the garage, added an isolation switch and put the CUs upstairs in a 'mission control' walk-in cupboard.

Good idea to put the henley block in possibly leaving a spare way for even further expansion. They might get a bit excitable if the henley block is before the meter !!

Good luck

Bob

[Colin Wilson]

Just call up the electric co. and ask them to do a check for safety / fit isolator... they`ll replace the tails for you, and should provide a double pole isolator so you can switch off your side of the installation.

The tatty tails to the meter are the responsibility of the electric co. (you have no "official" access to them as they`re sealed, so they should do it) - free of charge of course.

[Bob Eager]

As a matter of interest, would there be any advantage in pulling the neutral fuse as well? Is there any circumstance where this would be safer/less safe?

[Chris Oates]

Neutrals can have isolating switches (ganged with the live side) but never fuses

Broken neutral is (thinks hard) probably the worst fault you can have

[Colin Wilson]

Old iron clad "isco" cutouts (amongst others) had a fused neutral.

[Chris Oates]

I know - SEC had a laugh a few years back when they took ours out must have weighed as much as me

[Chris]

It was the black wire coming from the top of the white earth connection block I was in doubt about. Any ideas?

[BigWallop]

If you look at it carefully, you'll see that the black from the top of the white earth terminal is actually appearing as green/yellow cable from the left hand side at the back of the wooden board, so I would take it the black is only insulating tape wrapped around the green/yellow cable.

[Chris]

Seeing as you said please...... same URL (give it a few hours before it becomes available).

Chris

[Tim..]

*wants to see*

Tim..

[Owain]

"Chris" wrote | >| I didn't post make a picture of the consumer unit available | >| as I didn't want to scare anyone. | >Oh, please do! | Seeing as you said please...... same URL (give it a few hours before | it becomes available).

think that's where your enigma black earth wire goes :-)

I've seen worse. Far, far worse. It's when the fuse boxes are wood and the main switch is 2 5A tumbler switches with the dollies linked by a bar, then you know you've got an antiquity on your hands.

Owain

[Nic O'Demus]

Definitely a Henley block. Had a similar problem just this week. Supplier came to change a 3 ph meter with 2 sets of tails. Engineer said it was against regulations. Fitted Henley blocks so that only one set of tails was connected to the meter. Nic.

[BigWallop]

installation,

It's not that bad actually. I've seen worse. You've got an easy job there mate. :-))

[BigWallop]

If you're getting to the page OK, just wait a while and the pictures appear eventually.