What is the BS number is for this old DNO Crabtree enclosure?

Too_Wired · Feb 12, 2022

Hi,

I completed an EICR at a customer home in the week and came across this old Crabtree DNO equipment in the meter cupboard. Just two questions really

1. Does anyone know what the BS number of this equipment is (See pictures)
2. Will the DNO replace it if the customer requests an isolator switch fitted? (I'm quoting the customer on a new CCU) I ask because I've heard these old incoming DNO supply enclosures are not to be messed with, at all.

Thank you in advance

partplonker · Feb 12, 2022

Wouldn't the BS number be for the fuse inside it rather than the enclosure itself? Would guess 1361 (now BS88-3) but you'd have to open it to look at the fuse. It's a fine looking antique isn't it?

westward10 · Feb 12, 2022

Under no circumstances open it. It may well predate a British Standard and there is every chance it contains BS3036 semi-enclosed fuses, when I say fuses it may well have one through the neutral. It will almost certainly be replaced.

James · Feb 12, 2022

That also looks like a DIY earth connection.

partplonker · Feb 12, 2022

Is it wrong that I really want to see what's inside it? Could it really be 3036 fuse wire? Maybe a lovely bit of asbestos? Could there be a fused neutral? I find old gear fascinating.

Those tails coming out of it look like PVC so they've been updated at some point.

westward10 · Feb 12, 2022

You have no idea what is going on inside that enclosure just opening the cover could cause a disturbance, it doesn't take much for something catastrophic to happen.

partplonker · Feb 12, 2022

westward10 said:
You have no idea what is going on inside that enclosure just opening the cover could cause a disturbance, it doesn't take much for something catastrophic to happen.

I know, that's why the DNO guys have those heat jackets, gloves and the face shields in case the whole thing falls apart. Just curious, that's all

Too_Wired · Feb 12, 2022

partplonker said:
I know, that's why the DNO guys have those heat jackets, gloves and the face shields in case the whole thing falls apart. Just curious, that's all

I asked because I have no intention of opening it regardless of curiosity... just wondered if you'd come across them before. Also, there's tar leaking from the enclosure so I've requested the house holder contact their DNO to get it assessed ASAP.

ipf · Feb 12, 2022

Can't see it being anything other than 3036 with fused neutral, although tails replaced (within the last 40 or 50 years).
Definitely a case for DNO. They will change it and renew the main earth connection. Better be quick though, before it topples off the wall.

Better off if you contact DNO and explain the situation fully.

Too_Wired · Feb 12, 2022

westward10 said:
Under no circumstances open it. It may well predate a British Standard and there is every chance it contains BS3036 semi-enclosed fuses, when I say fuses it may well have one through the neutral. It will almost certainly be replaced.

Thanks for the feedback, I've heard similar things about these being a pandora's box of unpleasantires!

Too_Wired · Feb 12, 2022

ipf said:
Can't see it being anything other than 3036 with fused neutral, although tails replaced (within the last 40 or 50 years).
Definitely a case for DNO. They will change it and renew the main earth connection. Better be quick though, before it topples off the wall.

Better off if you contact DNO and explain the situation fully.

Mucho appreciated for the feedback

Too_Wired · Feb 12, 2022

ipf said:
Can't see it being anything other than 3036 with fused neutral, although tails replaced (within the last 40 or 50 years).
Definitely a case for DNO. They will change it and renew the main earth connection. Better be quick though, before it topples off the wall.

Better off if you contact DNO and explain the situation fully.

Just noted your request to contact the DNO. It's already underway and the landlord has been asked to advise them of the leaking tar from the enclosure. This installation has all kinds of Gremlins, but I suspect the issues stem from the various/random alterations done over time. Thanks again

Too_Wired · Feb 12, 2022

Thank you to everyone for their feedback

pc1966 · Feb 12, 2022

If you want to see why the DNO guys wear the arc-flash gloves and face mask when doing anything on supply fuses this video shows it in action:

Those guys were properly kitted out so probably OK, but I suspect their trousers fared less well!

pc1966 · Feb 12, 2022

westward10 said:
Under no circumstances open it. It may well predate a British Standard

Predating BS88 is a challenge, just the low number tells you something about the age of the fuse standard!

From memory it is something like 1921 it came out, so possible it predates it but you know what curiosity did to the cat.

westward10 said:
and there is every chance it contains BS3036 semi-enclosed fuses, when I say fuses it may well have one through the neutral. It will almost certainly be replaced.

Very likely. Certainly a "do not touch under any circumstances" item!

pc1966 · Feb 12, 2022

A check on BIS shop finds this withdrawn standard:

Electric cut-outs for low pressure Type O for ordinary duty with working currents not exceeding 100 amperes
BS 88:1919
Withdrawn 30 Dec 1918

How a 1919 standard can be withdrawn before it is issued is a mystery!

BS 88:1919 | 30 Dec 1918 | BSI Knowledge

BS 88:1919: The Standard for Electric cut-outs for low pressure Type O for ordinary duty with working currents not exceeding 100 amperes

shop.bsigroup.com

partplonker · Feb 12, 2022

pc1966 said:
Predating BS88 is a challenge, just the low number tells you something about the age of the fuse standard!

True. Even BS1361 dates to about the time we started using PVC cables in the late 50s/early 60s. There's still a slim chance that the cutout is not quite as old as it appears and there's a cartridge fuse in there.

I don't believe that meter is contemporary with the cutout either and if the cutout is as old and dangerous as feared, how would it have not been upgraded at the same time as the meter since they would have had to isolate it?

Perhaps if OP is there when the DNO removes it (unlikely I know) they could take a picture to satisfy our curiosity?

pc1966 · Feb 12, 2022

partplonker said:
I don't believe that meter is contemporary with the cutout either and if the cutout is as old and dangerous as feared, how would it have not been upgraded at the same time as the meter since they would have had to isolate it?

Probably 30-40 years ago folks were less safety conscious, and hardware like that 30-40 years younger as well!

I know a friend who has a cut out that is similar and almost certainly a fused neutral. But there is a whole lot of issues why I would not get involved there, as the property needs rewired as well as the DNO in to sort it. Unoccupied for a few years, think along the lines of Miss Havisham

Deleted account · Feb 12, 2022

westward10 said:
Under no circumstances open it. It may well predate a British Standard and there is every chance it contains BS3036 semi-enclosed fuses, when I say fuses it may well have one through the neutral. It will almost certainly be replaced.

I think your spot on there.

Exactly like one I had Western power out to.

It was fuse wire through both line nd neutral. it took 3 guys in 3 western power vans to discuss and desided to remove.

forst guy said it was fine, I disagreed pointing out the fuse wire to neutral. then his supervisor came out then a more experienced engineer came and did it.

Too_Wired · Feb 12, 2022

pc1966 said:
If you want to see why the DNO guys wear the arc-flash gloves and face mask when doing anything on supply fuses this video shows it in action:

Those guys were properly kitted out so probably OK, but I suspect their trousers fared less well!

Wow...!! The content on the video near the point of the explosion is really annoying but the message is clear !!