UK 100 Amps or 60 Amps

[AndyBuzz]

Hi guys - seeking an opinion or possibly experience of the same issue.
I have a spark engaged to do a fair bit of upgrade, been here for 35 years so current installation is well behind current regs !
The main job I asked the spark to do was fit a modern consumer unit in my outbuilding / garage. Rightly - he has gone back to the main board and advised the current armoured is only capable of 40 amps under current regs. However it did pass an insulation test. We plan to upgrade to 16mm for 60 amp capable so can later do an EV charge point . I've bought the ducting.
But - as my main house meter is old - he suggested asking for a smart meter - and at same time get an isolation switch fitted. Makes his works easier. Good idea and I arranged this with my Energy provider. It was fitted on Wednesday.
Not happy - he fitted an ordinary modern Economy 7 meter - not a smart one as promised.
Gobsmacked - he said FYI despite the main fuse saying 100 amps there is only a 60 amp fitted. He scratched up the 100amp label. He said refer to your power distributor.
So - question - has anyone come across a main fuse that says one thing and is fitted with another (less) ?
Where do I stand - it's never been touched since original installation.
Now I think I'm buggered. Can't run all that with 60 amp main fuse ?
My electrician says we are stuck and I have to contact SSE.
Does the power distributor have any responsibility ?
Many thanks

 

[Mikegh]

Not familiar with them

Presume it's just the unit is rate at 100a but only contains 60a fuse for some reason

 

[DPG]

Main fuse carriers often say 100A but have 60 or 80A fuses in them. The carrier is rated at 100A.

 

[brianmoooore]

As above. 100A is the maximum rating of fuse that can be fitted, if the supply cable is big enough.
'Standard' domestic supply is 15kVA, which equates to 65A.

 

[AndyBuzz]

Many thanks to both previous replies.
My spark assumed we had 100amps 'available'.
So are you suggesting that in a situation like this, my spark would break the seal to check what's really provided ?
I am not a spark but worked in Engineering for years. It seems very sloppy labelling by SSE and is misleading ?

 

[DPG]

Many thanks to both previous replies.
My spark assumed we had 100amps 'available'.
So are you suggesting that in a situation like this, my spark would break the seal to check what's really provided ?
I am not a spark but worked in Engineering for years. It seems very sloppy labelling by SSE and is misleading ?

It's very common. The fuse carrier itself is rated at 100A maximum. The fuse within can be anything up to this value.

I'm surprised your electrician didn't know this.

 

[AndyBuzz]

Ok thank you. I am better informed and learnt something
I also now know I can’t complain to SSE but ask for a survey to see what the feasibility is to upgrade the supply (and cost)
I fear it will be tricky as my supply is run through the middle of next door !

 

[timhoward]

I'm not an expert in EV chargers, but I'm given to understand that if you have a looped supply, and a 60 amp supply, then unfortunately both of these are hurdles that will need overcoming.
I've heard of instances where DNO (SSE) will unloop without charging. Others know more about this area of electrickery than me.

 

[buzzlightyear]

it is common knowledge now that the DNO are leaving 60amps in now
having to try balancing the loads better from the sub stations ,knowing the fact if everbody was on 100 amp the cable might snap crackle and pop.

 

[brianmoooore]

I'm surprised your electrician didn't know this.

It's worrying your electrician didn't know this.

 

[Mikegh]

Can the op not use the off-peak for the car charging then?

 

[buzzlightyear]

I'm surprised your electrician didn't know this

It's worrying your electrician didn't know this

I'm worried your electrician had not thought about that .
rephrase it IDIOT .lol

 

[AndyBuzz]

Thanks again for replies.
I've just looked up looped supply and now understand the concept.
Do SSE have accurate records of whether I am on a looped supply, and the supply cable size(s) ? 35 years ago !!
We are very rural, in one of a pair of cottages fed from overhead. The overhead runs about 400 yards to a more substantial set of overheads. I remember 35 years ago the linesman who installed our supply saying there is a 400 amp switch box there for isolating our overhead.
I think this might be expensive - or I just abandon it all and forget the EV charging 'future proofing'. Keep to petrol !!
I'll contact them tomorrow - maybe they will do a survey.
I'd have preferred my electrician to do this but he's ill at the mo.
Thanks all for your support and replies. Though I'm not an electrician I can understand all your replies and what the fundemental issues are.

 

[buzzlightyear]

you need to clarify with them ,they will know how and what you got.

 

[AndyBuzz]

OK just to close this - and I did ask before - how do you guys as sparks find out what fuse is actually fitted ? Do you check the main fuse (ie break the seal) or does the DNO have an accurate record that you can enquire.
Yes - I'm 'disappointed' my electrician didn't check this further - though he did comment that the incoming supply looked a bit small for 100 amps

 

[AndyBuzz]

OOps - Buzzlightyear - you answered my question !!

 

[buzzlightyear]

how do you guys as sparks find out what fuse is actually fitted

you can get a pair of xray glasses from amazon if that helps.
i have had mine over 40years now ,but not good when they steam up .lol.

 

[littlespark]

That’s the funny thing;
Our test certificates asks us to fill in a box what size the main fuse is…. But we are not allowed to pull it to find out

we have to go by the sticker on the fuse carrier… which in experience … is either “100A” or “60/80” which still doesn’t help… which is it? 60 or 80?
The carrier is moulded with 100A printed into the plastic, as others have said, that’s the rating of the carrier- the biggest fuse that can go in.

I’m surprised they didn’t fit a smart meter. I thought all suppliers were pushing for them.
I take it that’s because of rural setting and maybe bad mobile signal for the smart communications.

 

[DPG]

Thanks again for replies.
I've just looked up looped supply and now understand the concept.
Do SSE have accurate records of whether I am on a looped supply, and the supply cable size(s) ? 35 years ago !!
We are very rural, in one of a pair of cottages fed from overhead. The overhead runs about 400 yards to a more substantial set of overheads. I remember 35 years ago the linesman who installed our supply saying there is a 400 amp switch box there for isolating our overhead.
I think this might be expensive - or I just abandon it all and forget the EV charging 'future proofing'. Keep to petrol !!
I'll contact them tomorrow - maybe they will do a survey.
I'd have preferred my electrician to do this but he's ill at the mo.
Thanks all for your support and replies. Though I'm not an electrician I can understand all your replies and what the fundemental issues are.

Hopefully they may be able to sort it for you. Let us know what they say.

 

[pc1966]

Now I think I'm buggered. Can't run all that with 60 amp main fuse ?

The better EV charges have a current transformer for the main supply and will adapt the charging to keep your total below 60A (assuming the house is below 60 of course!)

So if charging and you put on an electric shower it just throttles the car charge for 10 minutes or whatever you are using it for.

Bigger issue is if you plan lots of electric heating or a massive range-style cooker, though I think some of the fancy induction ones also have total demand throttling (or am I imagining that?)

 

[freddo]

I’m surprised they didn’t fit a smart meter. I thought all suppliers were pushing for them.
I take it that’s because of rural setting and maybe bad mobile signal for the smart communications.

A couple of recent customers have told me they have been contacted by their suppler to book in fitting a smart meter only to be told they can't have one as they have off peak which isn't supported. The whole system is a joke.

 

[timhoward]

A couple of recent customers have told me they have been contacted by their suppler to book in fitting a smart meter only to be told they can't have one as they have off peak which isn't supported. The whole system is a joke.

We've also seen more than one example of this forum of smart meter installers not understanding off peak metering and having a go anyway, resulting in RCD's tripping every night...
It might not be such a bad thing if smart meter installers avoid these installations!

 

[AndyBuzz]

The better EV charges have a current transformer for the main supply and will adapt the charging to keep your total below 60A (assuming the house is below 60 of course!)

So if charging and you put on an electric shower it just throttles the car charge for 10 minutes or whatever you are using it for.

Bigger issue is if you plan lots of electric heating or a massive range-style cooker, though I think some of the fancy induction ones also have total demand throttling (or am I imagining that?)

Thanks pc1966
Interesting what you said on EV chargers with transformers.
Yes - the other thing I'd looked at is air source heat pump. My research suggests system design is a more constant background heating - less cyclic than your 20Kw typical gas boiler system. For larger older houses you'd need probably a min 4Kw system but run all the time in cold weather.
A lot of rural houses have no gas, so rely on oil / LPG. If this is phased out that leaves night storage / heat pumps.
Add EV to the equation and frankly I don't see how long term the grid will handle it all.

 

[AndyBuzz]

A couple of recent customers have told me they have been contacted by their suppler to book in fitting a smart meter only to be told they can't have one as they have off peak which isn't supported. The whole system is a joke.

Yes - the installer said that as it's economy 7.
Frankly I think I need to review the benefits now. Economy 7 used to be around half price. Now it's 22p day and 16p night, not a big difference any more.

 

[Julie.]

Thanks again for replies.
I've just looked up looped supply and now understand the concept.
Do SSE have accurate records of whether I am on a looped supply, and the supply cable size(s) ? 35 years ago !!
We are very rural, in one of a pair of cottages fed from overhead. The overhead runs about 400 yards to a more substantial set of overheads. I remember 35 years ago the linesman who installed our supply saying there is a 400 amp switch box there for isolating our overhead.
I think this might be expensive - or I just abandon it all and forget the EV charging 'future proofing'. Keep to petrol !!
I'll contact them tomorrow - maybe they will do a survey.
I'd have preferred my electrician to do this but he's ill at the mo.
Thanks all for your support and replies. Though I'm not an electrician I can understand all your replies and what the fundemental issues are.

When you apply for an EV charge point, you have to request permission from your supplier, it's a standard form which is available here https://www.energynetworks.org/assets/images/Resource library/Single-Electric-Vehicle-Charge-Point-and-Heat-Pump-Installation-Application-Form.doc

They then check their network diagrams, loadings etc before you can connect an EV charge point.

You can submit one yourself any time so consider putting one through and you will get your answer without any commitment on your part.

Note it's the same form if you want to install heat pumps as well.


Note, the fuse carrier states 100A as this is the maximum, just like a standard plug says 13A - you could have a 3A, 5A.... etc fuse installed.

One point is to look at the meter, it usually has a maximum of 80A, so that's a clear indication you wouldn't have a 100A fuse!

 

[AndyBuzz]

That’s the funny thing;
Our test certificates asks us to fill in a box what size the main fuse is…. But we are not allowed to pull it to find out

we have to go by the sticker on the fuse carrier… which in experience … is either “100A” or “60/80” which still doesn’t help… which is it? 60 or 80?
The carrier is moulded with 100A printed into the plastic, as others have said, that’s the rating of the carrier- the biggest fuse that can go in.

I’m surprised they didn’t fit a smart meter. I thought all suppliers were pushing for them.
I take it that’s because of rural setting and maybe bad mobile signal for the smart communications.

With all the regs changes covering even what sparks can have for lunch, I'm surprised that correct labelling of the main fuse isn't mandetory within regs. At work if we supplied any equipment everything HAD to be correctly labelled. Seems a bit odd to me that the DNO can have a blasé approach just because it's their fuse.
My main fuse was labelled 100amps, not moulded. The meter fitting guy scratched up the label so now you can't really read it at all.

 

[AndyBuzz]

When you apply for an EV charge point, you have to request permission from your supplier, it's a standard form which is available here https://www.energynetworks.org/assets/images/Resource library/Single-Electric-Vehicle-Charge-Point-and-Heat-Pump-Installation-Application-Form.doc

They then check their network diagrams, loadings etc before you can connect an EV charge point.

You can submit one yourself any time so consider putting one through and you will get your answer without any commitment on your part.

Note it's the same form if you want to install heat pumps as well.


Note, the fuse carrier states 100A as this is the maximum, just like a standard plug says 13A - you could have a 3A, 5A.... etc fuse installed.

One point is to look at the meter, it usually has a maximum of 80A, so that's a clear indication you wouldn't have a 100A fuse!

Thanks for the detail and esp the form link.
I have looked at my photo of the original meter - and yes it says 80 amps. Must admit I hadn't thought to look at it.

 

[Mikegh]

Can the op not use the off-peak for the car charging then?

I asked this ? I presume the economy 7 is the same as our day/night metering

Is there not enough spare capacity at night with the throttling u can do or is it because you specifically can't get permission on the 15kva supply here ?

 

[ferg]

In fairness to your Spark assuming that it was a 100 amp fuse installed is not the same as not knowing that it might not be.
Everyone makes incorrect assumptions at some point or another.
As previously stated some suppliers frown on pulling the main fuse.
Admittedly there were indications that it wouldn't be 100A but again it could have been a genuine mistake / brain fart / poor assumption rather than a lack of knowledge.

There is a thread on here somewhere about the daft things we have done as electricians that shows even talented knowledgeable tradesmen get it wrong sometimes.

 

[Colin Jenkins]

When you apply for an EV charge point, you have to request permission from your supplier, it's a standard form which is available here https://www.energynetworks.org/assets/images/Resource library/Single-Electric-Vehicle-Charge-Point-and-Heat-Pump-Installation-Application-Form.doc

They then check their network diagrams, loadings etc before you can connect an EV charge point.

You can submit one yourself any time so consider putting one through and you will get your answer without any commitment on your part.

Note it's the same form if you want to install heat pumps as well.


Note, the fuse carrier states 100A as this is the maximum, just like a standard plug says 13A - you could have a 3A, 5A.... etc fuse installed.

One point is to look at the meter, it usually has a maximum of 80A, so that's a clear indication you wouldn't have a 100A fuse!

Hello Andy.

Don't panic! The advantage of remaining at 60 amps if you can is that there is less fault energy present (therefore less damage) if something nasty goes wrong at the meter head or consumer unit. With LED lighting, improved insulation and improved technologies, domestic loads are reducing and you may be surprised to find your load current is significantly lower than the original circuit capacities. As posted above, many EV chargers can phase back when required to. I'd be surprised if a domestic cottage today got anywhere near to blowing a 60 amp fuse. Regards, Colin Jenkins.