Identifying / dating old service head?

tims22 · Dec 6, 2022

Hello, we're looking at relocating the CU fairly urgently for a small business (retail shop) and came across this service head. Obviously need to safely isolate ahead of working on the CU but not come across this type before. We're assuming the cut out is probably at least 50 or 60 years old although does look in surprisingly sound condition. The meter was replaced in 2015 and they didn't fit an isolator at the time.

If anyone is familiar with this type of cutout can you advise whether they're usually fuss-free to open or if we're likely to run into problems? Any tips from experience would be very welcome!
Plan B is disconnecting the meter <> Henley tails with the next stop being fitting an isolator before anything else.

Reason for the urgency is that the wall behind where the CU's located is in pretty dire condition & damp which has led to corrosion within the CU.. not a pretty sight and long overdue for replacement along with a partial rewire.

Thanks!

JBW175 · Dec 6, 2022

Just looks like a 3P&N service head that is only utilising 1phase.

Looks like a TNS earthing arrangement, but there is a lot of detritus around that area. Testing should identify if it’s true TNS.

Probably got a 1361 60 amp fuse in the cut out.

davesparks · Dec 6, 2022

tims22 said:
If anyone is familiar with this type of cutout can you advise whether they're usually fuss-free to open or if we're likely to run into problems? Any tips from experience would be very welcome!

As with any such service cutout it can only be opened by the DNO

tims22 · Dec 6, 2022

davesparks said:
As with any such service cutout it can only be opened by the DNO

Indeed - aware of that, thanks. We're also talking to UKPN at the moment.

HappyHippyDad · Dec 6, 2022

davesparks said:
As with any such service cutout it should only be opened by the DNO

Just reworded that slightly Dave.

tims22 · Dec 6, 2022

Thanks for the replies. I'd considered whether to post this and in hindsight should probably have realised that my hope of some input from someone who's previously encountered this form of cutout would have been overshadowed by another forum debate starting about the relative merits of pulling a fuse or not pulling a fuse. We all know that cutouts should only be opened by the DNO and we also all know that plenty of people pull fuses of all forms without a second thought and in plenty of cases with or without appropriate PPE if they have no other means of isolation. For clarity's sake, if we can get them to attend and fit an isolator, that would be great.

Might not be possible however for a whole variety of reasons, so was hoping to gather as much information as I can about what we've potentially got to deal with on the grounds that preparation usually helps everything go more smoothly. Haven't yet been able to find anything that looks like this particular cutout so had hoped someone might have encountered one in the past.

If you haven't - then many thanks for reading; appreciate your time. If you have, I'd love to hear more.

davesparks · Dec 6, 2022

tims22 said:
We all know that cutouts should only be opened by the DNO and we also all know that plenty of people pull fuses of all forms without a second thought

Yes but those are two different things!
Opening a cutout for whatever reason is very different to just pulling the fuse out of the front of it!

You asked about opening the cutout which implies that you are planning to remove the covers, presumably with a view to moving it yourself.

tims22 · Dec 6, 2022

davesparks said:
Yes but those are two different things!
Opening a cutout for whatever reason is very different to just pulling the fuse out of the front of it!

Yes - agreed! Presumably under the fuse cover on this one is an exposed fuse without the more "pullable" holder on newer cutouts, which puts the job in the territory of opening a cutout and presumably requires a fuse puller to extract.... and is one to leave well alone.

Hence asking the questions. I've not encountered this type before so before poking around wanted more information!

snowhead · Dec 6, 2022

This is what the Fuse carrier looks like inside, courtesy of John Ward video,,

[ElectriciansForums.net] Identifying / dating old service head?

littlespark · Dec 6, 2022

The bigger problem here is the OP “DIY” tag.

Speaking to other electricians about pulling fuses that know the risks… understanding what can and what can’t go wrong is one thing…. But we don’t know with a DIYer.

The advice has to be, get DNO to pull it… and if you’re interested, ask them if you can watch.

If you tell them it’s smoking, or smells funny… they might come out quicker

tims22 · Dec 6, 2022

littlespark said:
The bigger problem here is the OP “DIY” tag.

Speaking to other electricians about pulling fuses that know the risks… understanding what can and what can’t go wrong is one thing…. But we don’t know with a DIYer.

The advice has to be, get DNO to pull it… and if you’re interested, ask them if you can watch.

If you tell them it’s smoking, or smells funny… they might come out quicker

Ahh, good point. Picked "DIY" when I created my account as it seemed most appropriate at the time. Not strictly accurate though unfortunately and probably need to change it. Couldn't bring myself to pick "Electrical Enthusiast"

Didn't seem to be a suitable label - 25+ years of IT associated installation & cabling experience, plenty of hands-on electrical installation work in domestic (non-notifiable) and small business settings but never enough to tip the balance to go down the pro electrician route vs focusing on IT. Feeding that interest I'm now however a couple of weeks off sitting my 18th Ed exam (well, probably after the Christmas break) and will probably do C&G 2393 after that.

tims22 · Dec 6, 2022

snowhead said:
This is what the Fuse carrier looks like inside, courtesy of John Ward video,,

View attachment 104314

Thanks - can't imagine for one moment this one will be that straightforward. Not entirely sure which is newer though!

James · Dec 6, 2022

am I missing something here?
the cutout/fusecarrier looks fairly new to me and it has new colour tails that would have been 2004 onwards if i remember right.

50 to 60 years is in my opinion probably out by a good 30 years.

I know how i would isolate the distribution board but it is my secret and i am sure others have thought the same.

tims22 · Dec 6, 2022

James said:
am I missing something here?
the cutout/fusecarrier looks fairly new to me and it has new colour tails that would have been 2004 onwards if i remember right.

50 to 60 years is in my opinion probably out by a good 30 years.

I know how i would isolate the distribution board but it is my secret and i am sure others have thought the same.

Based on the attached label the meter was replaced in 2015 and we're guessing the cutout - meter tails were changed then as they seem newer than the rest of the install. Prior to that the last major electrical work was to fit a new CU in around 1987 and apparently the cutout has never been worked on according to the owner; who's had the building for 47 years.

I also have a "secret way" to isolate the board but always find it's better to have ones ducks, or seal fairies in a row before starting these things lol.

MJPD29 · Dec 6, 2022

I would say 1987 is around the time the cutout was fitted as well. It's definetly not 50-60 years old

Identifying / dating old service head?

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