Who owns what - your guide on cut outs, meters, fuses and who is responsible

Who owns what - your guide on cut outs, meters, fuses and who is responsible
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Updated on 16/09/21 by Jess_OVO


We’ve got an introductory guide on whose responsible for what with your meter and related equipment, for gas and electricity supplies here - for a more technical breakdown check out the user guide below:



The Meter Operation Code of Practice Agreement (MOCOPA) is between the UK’s Energy Suppliers and the Distribution Network Operators (DNOs).

The Agreement includes a document which classifies the way in which faults and non-compliances can be identified. It is well written, with numerous photographs.

It includes this excellent diagram, showing who is responsible for what in the area of your electricity meter:

The Agreement identifies faults with the Distribution Board (DB) equipment, which are the responsibility of the DNO. These are divided into three broad categories:

A: Emergency. A life threatening situation and requiring immediate action.

B: Remedial work required. Serious, requiring attention for safety reasons, but unlikely to cause a threat until it can be resolved.

C: Asset Condition; Requiring attention because it isn’t to the current standards.


Thus, by way of example, Code B11 Flow is a reporting category which prevents a Meter Installer from undertaking the work because there is a fuse on the Neutral supply as well as the Live.


Old Distribution Board equipment.

Sometimes there isn’t actually a fault, but your house appears to have old-style devices belonging to the DNO.

The Energy Networks Association publishes another guide with similar format, which enables such items to be identified. The Cut-out Types and Ratings Guidance  has full colour photographs and the date range when that equipment was fitted.


When viewing items of electrical equipment in your home, it is important not to tamper with it. If in doubt, take a photograph and post it here on the Forum for us to see.

42 replies

Userlevel 1

Thank you, Transparent.

The bitumen drippings looked solidified not liquid. So it happened some time in the past.

Thank you for this reply too. I will let them know so they can decide the apropiate action to be taken.


Userlevel 1

Hi Amy, thank you for your reply. 

I will see what UK Power Network will do, maybe will cancel my appointment too or maybe they will be able to fit only a 80 Amps fuse on the current existing meter tails (16mm) which is still a great achievement for my property.

My electrician will install indeed 2 x  100Amp isolation switches, one for each CU, in order to allow trouble free maintenance in the future.

Thank you very much for your help.



Userlevel 1

Hi @Tim_OVO , Given we are saying why can’t the DNO accept the say-so of the hosueholder or an electrician, why can’t Ovo do the same?

Userlevel 7

Had a good read of this, thanks for posting and sharing. That’s to you both. It’s valuable to have this online for reference. But that doesn’t matter as much at the moment. You, we, need to make sure you’re safe and that correct processes have happened. It’s certainly not too much to ask for in this case.

I won’t discuss your account, @killicrankie here. For your privacy but also due to my responsibilities under GDPR. But you can certainly keep us updated here if you wish. What I would suggest is we keep in mind the lack of certainty. And the existence of subjectivity, from engineers and professional electricians and everyone in between. People have made observations and we don’t yet know the facts 100% ….. yet. 

So let’s confirm them. @killicrankie if you haven’t already, please ring our support line, who will be able to put in motion a checking of the engineer report and if need be a conversation between someone and the engineer. The next port of call is a DNO conversation, probably best done by OVO. I might be wrong, (caveat) but that puts my mind at ease a bit. Hopefully you agree @killicrankie - 0330 303 5063. We’re open from 8am Friday morning.

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Well I was actually expecting a photo of the entire Distribution Board @killicrankie !

But I think we’ll agree that the word “asbestos” is printed on your fuse. At this stage, that’s not a safety issue of any great priority @Tim_OVO. The asbestos isn’t fractured and is sealed within the carrier. Also the fuse is operational.

So that still means the highest priority is the Category-B11 (fused neutral)…. for which I’d like to see a photo of the Service Fuse carrier in the context of the whole board if possible.

And that would be the most instructive/helpful upload to this Forum thread. I think we’d like customers to become more aware of the ownership and condition of their board using their eyes (no tools!). So pics uploaded to this Topic will help steer us in the right direction.

Userlevel 1

Ok, I'll see if I can get s good clear shot and upload it.

Userlevel 1

Here's a more complete shot of the board.


Userlevel 1

Hi thank you for your reply.

Reason for fuse upgrade is that I need more Amps available for house as I will have a summerhouse CU installed soon, so more power demand overall.

Yes you are correct, the OVO engineers can change meter tails as Ovo owns the meter.

On UK Power Network it is clearly stated that the meter tails must be upgraded by the energy supplier BEFORE they can upgrade the fuse.

However because OVO it seems to be useless, I have contacted UK Power Network again and asked for a revised upgrade to 80 Amps only. This will be possible on the current meter tails size of 16mm hopefully. It is still a step forward for me.

Yes if the UK Power Network will decide that the whole fuse box needs to be changed because of visible damage or overheating, then probably they will break the seal on the top part of the fuse box where meters tails are fitted and be able to put new meter tails too at the same time with replacing the entire fuse box. It makes sense to me and hopefully this will be the case as I noticed some kind of black asphalt kind of leakeage along the fuse box, God knows from when, as the house electrics have been done in 1976 and I bought it as it is in 2012.


Thank you for your reply.






Userlevel 1

Hi Transparent, thank you for your reply.

But I think you are very mistaken.

OVO MUST change the meter tails BEFORE the fuse is changed by UK Power Networks (DNO equivalent in my area). It is a common sense procedure. You can't let more power into the house by changing fuse when tails size might not cope with it. 

Also stating that DNO (or UK Power Networks in my case) might change the tails, it is again a HUGE untrue statement.

For DNO to change tails will need to break seals into the meter and the meter belongs to my Ovo energy supplier, so they will not do it.

Why are you providing false and misleading information?!

I was hoping on this forum I can find good answer.

My problem was related only to OVO handling very badly the meter tails upgrade appointment, blaming it on lack of engineers in my area. 

They booked me, they took my money  then a week later they cancelled my appointment.

Now they are playing the very hard to reach to try to book another appointment.

I just wanted to hear of similar experiences with other forum members.




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Well I think @Adiavel ‘s idea of requesting an 80A fuse is a masterstroke. I doubt that the DNO holds many of those in the stores. So there’s a fair chance they’ll turn up with a standard 100A fuse anyway!

Just returning for a moment to the additional Consumer Unit you want to put into the summerhouse, I’m unsure how your local electrician might wish to link that to your existing Distribution Board. There are a number of alternatives, dependent on the type of cable (Steel Wire Armoured underground?) and what mechanical space there is in your existing CU.

When I started a house renovation about 5 years ago, I had the DNO relocate my meter into a new box built into the external wall. The existing arrangement was a mess of three CU’s, two with re-wireable fuses. So my friendly electrician placed a new 100A Switch Disconnector in a separate box screwed to the internal wall just behind the meter enclosure.

The DNO engineer arrived mid-morning, fitted the Service Fuse and meter, which had short tails running through the wall to the new Switch. He performed the required tests and left site.

My electrician called by a couple of hours later, made safe the loose cable-ends around the consumer units and ran an overly-long pair of new tails to the other side of the same 100A switch.

Each party had completed the work for which they had responsibility. But the arrangement allowed us several months to gradually run new cables through the house as the renovation work continued. Whenever we had a new circuit ready we could isolate everything without needing to call the DNO to pull their Service Fuse.

Anyone considering future changes to consumer units (perhaps for an EV charger) should ask their electrician for the same arrangement. It’s cheap, practical and safe.

Userlevel 6

Hey @Adiavel, I’ve been in touch with our operations team to ensure the information I give is fully accurate.

It’s a shame to hear the appointment has been delayed, but the DNO won’t touch the meter tails at all, it will be in your best interest to wait for the appointment. It's best practice that we upgrade the tails before the fuse is changed. 

I'd also recommend having an isolation switch installed if you don't already have one, if you’re planning on having two consumer units.  It'll make it easier for the electrician to wire. We can do meter tail upgrade and isolation switch fitting in one job, no problem, please reach out to the team, you’ll find our contact details in the post earlier by @Tim_OVO

I hope this helps! 

Userlevel 7
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Any update on this please @Adiavel ?

Userlevel 7

Hi @Transparent can you help me so we can strip out the specifics of this post, making it more applicable to users who want to know who’s responsible for what, and how they can get the help they need. We’ll need to remove bits referencing killicrankie’s issue. If you’re happy for me to do this, just let me know! I don’t know if you’ll have edit rights at this point. 

Userlevel 7

Hi @Tim_OVO , Given we are saying why can’t the DNO accept the say-so of the hosueholder or an electrician, why can’t Ovo do the same?


I understand the logic behind this, but I think suppliers and DNOs will insist on visual confirmation before assigning priorities for work. It’s important to get right!


@Transparent shall we add bit for who to contact (i.e suppliers, electricians, DNOs ), and link out for each one so our members can easily find their/our contact details? 

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I think @killicrankie still has a valid point. A customer’s photo of the current installation is a great deal cheaper than sending a meter installer to site, especially in cases when it’s already known that the DNO will be required to do work first!

There’s a list of DNO contacts on the last page of the Cut-out Types and Ratings Guidance which I mentioned above. We could improve it by finding out a more precise email address to where a photo could be sent. But equally, that information will gradually age here on the Forum.

Userlevel 1

Thanks @Tim_OVO . Let’s not forget the customer experience in all of this. 

Firstly, there’s the risk of a potentially dangerous situation. A two-visit approach means twice the wait to resolve a situation. It seems to me that DNO engineers, Ovo engineers and qualified electricians should all be reasonably well suited to spot these situations and “get right” the solution and most importantly get it fixed as soon as possible.

Secondly, especially where we are at the moment with the pandemic, we’re looking at two engineer’s appointments for the customer, with two 6-hour visit slots to manage and two visits into the home presenting extra contacts for the homeowner and engineers alike.

Userlevel 7

A two-visit approach means twice the wait to resolve a situation. It seems to me that DNO engineers, Ovo engineers and qualified electricians should all be reasonably well suited to spot these situations and “get right” the solution and most importantly get it fixed as soon as possible.


It’s a good point I must say. I’m playing devil’s advocate when I counter btw. I’m not privy to the logic behind the process at all. But perhaps if they allow an electrician (or a photo to a supplier) be the judge of an emergency, and the DNO visit very quickly as a result. and it is NOT a category A, maybe another category A visit has been delayed, with possibly lethal consequences….


Secondly, especially where we are at the moment with the pandemic, we’re looking at two engineer’s appointments for the customer, with two 6-hour visit slots to manage and two visits into the home presenting extra contacts for the homeowner and engineers alike.


 This is a very good point, and I’m certain the process wasn’t created with COVID social distancing in mind. How did things go yesterday, @killicrankie ?


@Transparent this bit of content is fantastic. It’s now online for OVO members and non members. It will have value for months and years to come, so great job getting this posted! Where are we at with our other planned tutorials? Pictures but not much text as it stands. I’ll be waiting to support when this gets filled out more, so let me know! 

Userlevel 1

Hi @Tim_OVO  - the visit is tomorrow. Hopefully, we’ll get to the next step quickly and if the DNO is quick, we might make it inside 28 days. I’ll let you know.

Userlevel 7
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@Tim_OVO - if the suggestion we’re discussing here is implemented, then it’s up to the DNO to view the photo of the Distribution Board and decide if they’re happy with it being classified as Category-A. It shouldn’t matter whether the photo and suggested classification has come through an OVO Engineer working to the MOCOPA scheme, or directly from a customer such as @killicrankie.


And also, can you please ensure you grab a copy of the two PDFs we’re referring to in this Topic. If either of them get withdrawn or moved from their current location, we’ll need to upload them somewhere else on the OVO site in order to keep the Topic “live”!

Userlevel 1

Hi @Tim_OVO , bad news I'm afraid. We didn't get it done, right or otherwise. As far as I am aware nothing was done about the cutout, just a smart meter installed. Let me know what you want me to do to get this fixed. Only a few days left of the 28 allowed.

Userlevel 1

Just a heads up. I definitely wouldn’t recommend booking in a smart meter replacement appointment to get an issue like this solved. We’re frankly no closer to a solution.

I now have an electrician reporting a B11 issue (which needs to be dealt with in 28 days) and Ovo reporting a C03 issue (which is optional to fix).

This means two experts who disagree but are not allowed (by processes) to discuss it and agree who has responsibility for the fix. As such, I can’t go ahead and get my EICR completed without 1) changing energy supplier or 2) changing electrician.

Seems bonkers, and as the issue is closed from Ovo’s point of view, it’s back on me.

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I think @killicrankie that we should ask @Tim_OVO to run this past one of OVO’s Staff who train their SMETS installers. (They have a high-quality in-house training suite).

The Faults and Non-Compliances section of the MOCOPA Agreement gives a hierarchy to help engineers decide which code to assign to an installation where there is more than one fault present on the DB (ie a fault that is the responsibility of the DNO).

As the OVO Installer has completed the meter installation, he may not now report a Code-B, even though it is clear to us that having a fused neutral is indeed Code B-11. See the rules at the top of Page-4.

Category C03 is the one which most closely matches the required fault-report code in that it informs the DNO that they will need to replace the Service Fuse assembly in its entirety.

I can’t see anywhere in the document which suggests that a Category C is optional for the DNO. It will get flagged as a Asset that fails the required specification, and must still be attended to.

There remains the question as to why OVO’s Engineer proceeded to install the Smart Meters despite there being a fused-neutral. Doing so has removed the requirement for another site visit, but denied him the possibility of notifying your DNO of a Category-B fault. It has saved the additional costs, but has it done so at the expense of a higher level of safety warning being issued?

That’s something which OVO needs to evaluate. And that’s why this would seem to be a good example of a situation which could be brought up in the Training Dept. Let’s see what @Tim_OVO thinks.

I’m sure we’d all like to hear when your DNO attends on-site and whether they choose to comment on the Fault Category which has been assigned.

Userlevel 1

Hi @Transparent , thanks for your detailed reply. I did look at the MOCOPA agreement and saw that in the case of an identified B11, all work should stop immediately, the householder informed and the DNO notified. 

I assumed that it was optional as Ovo’s customer service guys said that I could choose to contact the DNO and ask them to do something about the 60A rating of the service and by the fact that the MOCOPA agreement does not require the engineer to inform the householder, which he did not. I guess I’ve interporetted that one incorrectly.

I’m afraid I don’t understand the logic behind removing the requirement to report a more serious error. It seems odd that not following procedure (assuming my electrician is correct and per the photo of the asbestos fuse I’ve just provided to Ovo customer support) that this should lower the category of fault.

It seems to me that it’s not only at the expense of a higher level fault, but at the expense of the customer in this case.

Userlevel 1

Just reread the MOCOPA agreement. Under the category C preamble it does mention not telling the householder as it will create an “unreasonable expectation of DB intervention”. Reporting is clearly manadatory, but this suggests that in some cases nothing will be done.

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Is there any chance of you posting that photo here please @killicrankie ?

There are now three possible issues in play:

  1: there is a fused Neutral; category B11

  2a. the fuse rating is 60A (which is possibly due to the Feed being 16mm² or less)

  2b. the fuse rating is below 60A, in which case category C03 is actually correct

  3: the fuse carrier contains asbestos; category C11 applies

Whatever the MOCOPA document and OVO’s Training stipulate, there’s no reason why these shouldn’t be altered if needs be. Isn’t it because of such feedback that we continually revise safety documents anyway?