Replace main fuse to allow smart meter installation

Strummer22

I have a 3-phase electricity supply at a mixed residential/commercial property, which is a fancy way of saying it's a smallholding. I am interested in getting a smart meter fitted.

When the smart meter installer finally sent an engineer competent to deal with 3-phase after 3 (or was it 4?) failed attempts, the engineer advised he couldn't fit the smart meter as our main fuse is rated 160A and would need to be replaced with a 100A fuse to allow a smart meter to be fitted. Note that we don't need a 160A fuse - there used to be very high demand here, previous owners ran a haulage business and had high powered compressors etc, no longer in use. 

My money saving question is: how much might it cost to replace the main fuse? We're in Tameside, Manchester, so I assume this has to be done by Electricity Northwest (although I'm not clear if we could get a private contractor to do it - any ideas?). Does anyone have any idea of the ballpark cost to get this done? 

Thanks in advance

CSI_Yorkshire

Yes, it's an ENW job.

connectionapplications@enwl.co.uk or 0800 988 1730

dunstonh

My money saving question is: how much might it cost to replace the main fuse?

Normally they do not charge for fuses upto 100A.    However, you are an unusual case of going backwards rather than forwards.  

Are you sure you want to go backwards?   And are you sure its the 160amp that is causing the issue and not the three phase?

Strummer22

dunstonh said:

My money saving question is: how much might it cost to replace the main fuse?

Normally they do not charge for fuses upto 100A.    However, you are an unusual case of going backwards rather than forwards.  

Are you sure you want to go backwards?   And are you sure its the 160amp that is causing the issue and not the three phase?

Thanks, the smart meter company was fine with it being 3-phase, once that fact had finally filtered through from our supplier to their bookings team and finally to the engineer who attended (hence the several failed visits!).

It's definitely the fuse. I don't think there are any smart meters rated to 160A and presumably they don't have in-built protection. Too much current and the smart meter would, well, I dunno. Melt? Anyway, apparently that's the problem.

We have no need for 160A. We have got a GSHP and may install EV charging in the future but these plus all household use won't draw near 100A; just checked the GSHP specs and the recommended external protection is 16A. 

If ENW will do it for free that would be lovely. If it costs even just a few hundred I probably won't bother as it'll take a lifetime to make that back from the time of use tariffs or other benefits that a smart meter might open up.

[Deleted User]

Looking at the technical specification for a couple of common domestic smart meters the maximum rating is 100 amps. The issue is not that the meter becomes unsafe per se but it appears to be related to metering accuracy.

FreeBear

Strummer22 said: We have no need for 160A. We have got a GSHP and may install EV charging in the future

As you have an intention to install EV chargers, insist on an isolator switch fitted between the meter & consumer unit. This will enable the EV charger installers to isolate the supply without pulling the main fuse(s). Although an isolator isn't a legal requirement, it is considered "best practice" from a safety issue and your EV installer may insist on one.

Your electricity supplier should be able to fit one, often at no charge (Eon did for me). Just make sure they know when booking the smart meter install (again).

Ectophile

I'm not sure why you would voluntarily pay to have your electricity supply downgraded.  If they want to do it to fit their meter, let them pay.

Strummer22

Ectophile said:

I'm not sure why you would voluntarily pay to have your electricity supply downgraded.  If they want to do it to fit their meter, let them pay.

The smart meter is optional. The supplier is not insisting on it.

CSI_Yorkshire

Strummer22 said:

Ectophile said:

I'm not sure why you would voluntarily pay to have your electricity supply downgraded.  If they want to do it to fit their meter, let them pay.

The smart meter is optional. The supplier is not insisting on it.

Plus I think it's likely that they would do it for free.  Reducing capacity is normally a free service (although normally only applies to large commercial customers).

Scot_39

Surely if 3 phase supply that's 100A per phase fuses - plural

But the op may only have single phase distribution in the section of property he is talking about when adding up ev, gshp etc.  So constrained by 100A.

But possibly the gshp or ev charger could go on other phases - with a suitable isolator connection.

If locations etc suitable.

There are 3 phase smets2 meters - and units like aclara's 1430 are 100A per phase.

The 100A is a physical current limit - for meter and the meter tails that fit into its terminals.

25mm2 for 100A tails

And the idea is the fuse protects cabling - it melts not the cables or meter.

The aclara meter says it's in built protection is 100A.  It's cable terminals sized to match  I assume.

Certaily sone henley blocks are 25mm2, but others are 35mm2.

And some cable suppliers quote 35mm2 (others 50mm2) for 160A depending on temp profile and cooling (buried, conduit, free air etc).