Request for DNO to move meter indoors?

[tonyelectric]

Hopefully they won't go that mad, but i'm on 258 here, substations next door buzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

 

[tonyelectric]

(voltage goes down, current in their wiring goes up = bad)

Well if the supply wiring is undersized the cable will be overloaded, and then possibly overheat, we has one round here that was running 190 for quite a while, they did nothing, then the oil in the transformer caught light and it made the news, apparently the current was too much for the copper strips linking the secondary to the back of the insulators, it had been set on the wrong tapping

 

[ricicle]

Well if the supply wiring is undersized the cable will be overloaded, and then possibly overheat, we has one round here that was running 190 for quite a while, they did nothing, then the oil in the transformer caught light and it made the news, apparently the current was too much for the copper strips linking the secondary to the back of the insulators, it had been set on the wrong tapping

Do you remember Ohm's Law Tony ?

 

[tonyelectric]

hmm yep your right Ricicle, couple of beers and the brains gone soft good old ohmy

 

[ban-all-sheds]

Currently have an external meter box fitted to our property, which, to be honest, is pretty darned ugly. Its of the recessed type.

Smarten it up, then. Replace the door? Clean it & paint it?

I am looking to get this changed to TNCS with a 100Amp supply....I need to install a 60A fused isolator (plus associated 2 pole henley blocks) and a second meter for a submain and there is insufficient space.
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<etc etc>

Leave the meter where it is.

Give your electrician the task of getting the cables from there to the new CU position with the minimum disruption/cosmetic issues.

No probs if I have to pay to upgrade, thats fair enough.

Do come back and tell us if you still feel the same after you've had their quote...

 

[mbga9pgf]

Give your electrician the task of getting the cables from there to the new CU position with the minimum disruption/cosmetic issues.

Looks as if I am chasing out then doesnt it! Seems bl00dy ludicrous to route 25mm cable UP the same wall that 25mm incomer cable routes DOWN from...

 

[ban-all-sheds]

So the overhead cables arrive at the building at eaves height, and then run down the wall to the meter box?

 

[mbga9pgf]

So the overhead cables arrive at the building at eaves height, and then run down the wall to the meter box?

Yep,

Untitled

• mbga9pgf
• 28 Dec 2010
• 1

If you look on the pic, the insulators are above the left hand windows above the first floor. The cupboard I was hoping to move the meter to would have the wire entering the property level with the base of the window, between the window and the downpipe. From there it would run straight to the meter and service fuse. The meter box is behind the (ugly) porch, so, in effect, I would have 1 wire down, to the meter+ tail back up to the window, which is quite difficult as I understand 3 metres is all you get as far as tail length goes...

 

[ban-all-sheds]

Varies from DNO to DNO, but 3m is typical for unprotected tails.

But if the meter box currently has the CU in it then there must be room for a switchfuse when that's gone.

Or use SWA or MICC instead of 6181Y.

The meter box is behind the (ugly) porch.

Could the CU go inside the porch if you put a door on it?

(ugly) porch

http://www.canopystore.co.uk/admin/run.cgi?prog=publish&category=various&session=canopystore

 

[Stoday]

They will need to change the meter too, its only rated at 80A.

A meter rating of 80A does not mean it is overloaded at 100A. The rating is a calibration rating, that is, the meter is tested to be within tolerance at 80A. Even if your cutout fuse were upgraded to 100A your meter would not be changed.

 

[mbga9pgf]

They will need to change the meter too, its only rated at 80A.

A meter rating of 80A does not mean it is overloaded at 100A. The rating is a calibration rating, that is, the meter is tested to be within tolerance at 80A. Even if your cutout fuse were upgraded to 100A your meter would not be changed.

OK. good news.

Bad news, just been back to the house and I am recording a pretty large voltage drop on a minimal current draw on the system.It looks as if the DNO has connected the system with at best 10mm cable.

Voltage with no draw = 242 volts

Shower + oven on (approx 45 amp draw) the voltage across the incomers drops to 223 volts..This could indicate a serious fault at some stage in the overhead or supply cables or incorrect cable sizing. Even assuming 6mm2 cabling and a run of approx 4 metres (pessemistic) I am calculating a volt drop of 1.3 volts, not the 19 volts I am recording. The only potential snag I can think of is the overhead cables are undersized when the length from the transformer is accounted for. I estimate a 200m run.

All I know is, if we draw the rated current of 80A, the volt drop in the supply will be well below that permitted and potentially lead to damage to sensitive electronics in my home.

What should I do? What would be the best way to get the DNO to accept their supply doesnt meet regs if current is at the max specified? Or will they tell me to ram it? Just spoke to the DNO and our agreed capacity is 18KVA, so that isnt the problem.

 

[Stoday]

If you make a voltage complaint, the DNO will eventually (usually after some argument) connect a recording voltmeter to your supply for a month or so. If the voltage is always 216V or more, they'll take no action. They will not estimate the voltage drop at 80A.

 

[bernardgreen]

You could try telling the DNO that at a 45 amp load there is a 19 volt drop in supply voltage. This equates to 855 watts of energy being dissapted between their transformer and your incoming mains.

They may then be a bit more worried that something in their system is dissapating that much heat.

Two watts per metre of heating in a supply cable ( four if the phase and neutral are in the same cable sheath ) might be acceptable to them but it would worry me.

 

[mbga9pgf]

Messaged the DNO. Got a phone call within 15 mins; they are going to get a test engineer out to the house next time we are there.

Very suprised about how quickly they got back in touch.

 

[aptsys]

TNCS is certainly better earth wise

Sweeping statement. There's pros and cons to both TNCS and TT.