Fuse panel hot unit, smell in corridor below?

JohnW2 · 17 Jun 2021

sparkwright said:
a) I don't think there is an electric meter in the land which has a terminal layout any different to L in, N in, N out, L out.

You may well be right in terms of single-phase meters - I certainly can't cite an example which contradicts what you are saying. However, for what it's worth, my 3-phase meter is very different, with the 'neutral in' and neutral out' terminals being the right-most two ...

sparkwright said:
b) Would be worth looking in the CU, yet it would seem polarity is already wring by the time it gets to the meter, so if polarity was restored by the time it gets to the cu, the meter at least would still be connected wrongly.

True, but I don't think that would matter as far as the meter is concerned - all it knows is that there are two conductors (with a pd. between them, and with the same current, in both magnitude and phase going through both), and it doesn't really care which one is closer to truth earth potential.

Are you still seriously entertaining the thought that the DNO may have put a fuse in the neutral of their supply?

Kind Regards, John

sparkwright · 17 Jun 2021

JohnW2 said:
Are you still seriously entertaining the thought that the DNO may have put a fuse in the neutral of their supply?

Only because you indicated the possibility of it in post number 6 .

SUNRAY · 18 Jun 2021

The meter in my first house was wired Black, red, red, Black with single insulated rubber tails. Assuming it was correct I replaced with PVC (with agreement with supplier as part of timber/damp treatment works), they came to inspect/reseal and the only comment was the 16mm² earth lead should only be 10mm². It was discovered about 4 years later by a meter reader.

JohnW2 · 18 Jun 2021

sparkwright said:
Only because you indicated the possibility of it in post number 6 .

Eh? I'm getting rather confused. In post #6, I was "questioning (not 'indicating') the possibility" which you has seemingly asserted in post #5 ...

sparkwright said:
Black neutral wire looks a bit skinny where it enters the service head ....

(the 'service head' being the DNO fuse holder).

Kind Regards, John

JohnW2 · 18 Jun 2021

SUNRAY said:
The meter in my first house was wired Black, red, red, Black with single insulated rubber tails. Assuming it was correct I replaced with PVC (with agreement with supplier as part of timber/damp treatment works), they came to inspect/reseal and the only comment was the 16mm² earth lead should only be 10mm². It was discovered about 4 years later by a meter reader.

Fair enough, but (a) did "black, red, red, black" correspond with the traditional "L, N, N, L" and (b) which colour was treated as L and which treated as N when it got to the fuse box/DB/CU/customer fuses/whatever?

Kind Regards, John

SUNRAY · 18 Jun 2021

JohnW2 said:
Fair enough, but (a) did "black, red, red, black" correspond with the traditional "L, N, N, L" and (b) which colour was treated as L and which treated as N when it got to the fuse box/DB/CU/customer fuses/whatever?

Kind Regards, John

N, L, L, N. I wouldn't have done the colours wrong.

JohnW2 · 18 Jun 2021

SUNRAY said:
N, L, L, N. I wouldn't have done the colours wrong.

Ah, so do I take it that you were dealing with a meter which was 'not in the land', per ....

sparkwright said:
a) I don't think there is an electric meter in the land which has a terminal layout any different to L in, N in, N out, L out.

Kind Regards, John

EFLImpudence · 18 Jun 2021

JohnW2 said:
Are you still seriously entertaining the thought that the DNO may have put a fuse in the neutral of their supply?

What a peculiar line of thought.

Surely they haven't "put a fuse in the neutral of their supply" but simply connected the black tail to the Line/fuse terminal.

sparkwright · 18 Jun 2021

JohnW2 said:
Eh? I'm getting rather confused. In post #6, I was "questioning (not 'indicating') the possibility" which you has seemingly asserted in post #5 ...
(the 'service head' being the DNO fuse holder).

Kind Regards, John

In post 5 I simply noted a black tail which I naturally assumed to be a neutral, you then quite correctly pointed out it wasn't in the expected terminal at the 'service head' or DNO fuse holder.

Your questioning indicated a potential problem.

Why are we going round and round and round in circles over this?

We have found there is very good chance the polarity is reversed in this place, and we are still talking in riddles.

JohnW2 · 18 Jun 2021

EFLImpudence said:
What a peculiar line of thought.

It would certainly be an extraordinary, and almost unthinkable, thing for a DNO to do.

EFLImpudence said:
Surely they haven't "put a fuse in the neutral of their supply" but simply connected the black tail to the Line/fuse terminal.

Exactly. That's what I said right at the start, when I pointed out (in post #6) that sparkwright was (hopefully) wrong in describing the tail coming from the fuse as 'neutral' ('because it was black'), when I wrote (although I'm coming to regret that I opened my moith

) :

JohnW2 said:
Are you talking about the black (insulated and sheathed) 'tail' between the DNO fuse and meter? If so, despite it being black, it is hopefully not the neutral

However, things have moved on from then. You and sparkwright have pointed out that IF the meter terminals are in the traditional order (unlike Sunray's meter!), then it would seem that the {actual} L enters the CU as a black tail (and the {actual} N as a red tail) - which now makes it important to know 'which way around' those tails are connected within the CU, doesn't it?

Kind Regards, John

JohnW2 · 18 Jun 2021

sparkwright said:
In post 5 I simply noted a black tail which I naturally assumed to be a neutral, you then quite correctly pointed out it wasn't in the expected terminal at the 'service head' or DNO fuse holder.

Indeed, and that was the one and only reason for my comment.

sparkwright said:
We have found there is very good chance the polarity is reversed in this place, and we are still talking in riddles.

It does seem quite possible - so, as I wrote back in post #14:

JohnW2 said:
.... To be sure what was going on, we would presumably need to (a) be certain that our assumption about the meter terminals is correct and (b) see inside the CU to see what is connected to what at the Main Switch.

Kind Regards, John

sparkwright · 18 Jun 2021

Looking at the picture again, on the service head it may not be the case that the black wire goes into the fuse.

There is a short stumpy box bit, then the longer fuse carrier bit - so the black may go to the short stumpy bit and the red to the longer bit. (Technical this.)

Could well be an optical illusion throwing us out.

Guitarguy · 18 Jun 2021

The service head is the ‘upside down’ fuse on the left hand side nearest the meter so the black and red tails are in the correct place it just looks odd! It’s not wrong it’s just like that to save crossing the incoming conductors over too tightly and that would be difficult to make a cutout off like that

ericmark · 18 Jun 2021

I thought the question was all about a box getting hot? And all I can think of is remove a fuse at a time until it cools, but unless on its own fuse that will not help, it will mean removing the fuse box cover to disconnect what ever it is.

If it is a bell transformer then may be the supply to bell is shorted out? could look for old bell wires, likely at front door and see if ends are shorted out, had that before where new wireless door bell fitted and old wires left powered up.

With the ding dong door bell if the button sticks in it can cause transformer to over heat, often the bell uses 1 amp and transformer rated ½ amp, but pressed for such a short time it does not matter, so stuck door push first to look at.

SUNRAY · 18 Jun 2021

JohnW2 said:
You and sparkwright have pointed out that IF the meter terminals are in the traditional order (unlike Sunray's meter!),
Kind Regards, John

I seem to have misled with this point,
My meter was totally conventional with neutral in the middle, however when I purchased the property it was wired with red lives in the middle and not givng any thought it may have been wrong I replaced the tails to a similar standard.

The error was noticed by the meter reader about 4 years or so later. When SEEBoard came to correct it they replaced the neutral fuse in the CI head with a link and also upgraded to 60A and a bigger meter.

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Fuse panel hot unit, smell in corridor below?

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