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

[Too_Wired]

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]

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]

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]

That also looks like a DIY earth connection.

 

[partplonker]

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]

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]

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]

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]

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]

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]

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]

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]

Thank you to everyone for their feedback

 

[pc1966]

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]

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.

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]

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!

Loading...

 

[partplonker]

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]

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]

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]

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 !!

 

[pc1966]

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

There are a couple of videos showing the risk from a high energy fault. Most domestic work is after the main fuse but that is bad enough, post-DB it is slightly less risk as PSCC less and OCPD fast, but really it illustrates why you should do safe isolation and use CAT-III or CAT-IV test gear.

Also note the overalls as such arc-flash can give 3rd degree burns at short-medium distances before you can get your sorry behind out of there. Fire-retardant cotton ones like welders might use are sometimes rated for the basic arc-flash protection as well, but if working on big systems then appropriate risk assessment and PPE should be used.

Never wear nylon or similar garments close to such work as under arc-flash is melts and sticks to the skin making the injuries worse than cotton or similar natural fibres that might burn but don't do that.

Here is another video on fuse versus MCCB, not the most exciting viewing for a Saturday night but still shows the point about being able to safely break the PSCC in larger systems:

 

[partplonker]

Also note the overalls as such arc-flash can give 3rd degree burns at short-medium distances before you can get your sorry behind out of there. Fire-retardant cotton ones like welders might use are sometimes rated for the basic arc-flash protection as well, but if working on big systems then appropriate risk assessment and PPE should be used.

It's improvising a bit, but the very odd time I've had to pull a scary fuse I've used welding gloves and a face shield just in case. Your limbs and eyeballs aren't replaceable.

 

[pc1966]

It's improvising a bit, but the very odd time I've had to pull a scary fuse I've used welding gloves and a face shield just in case. Your limbs and eyeballs aren't replaceable.

Very true!

I should have made it clearer that I meant the overalls in addition to suitable gloves and a mask!

I have some "you have been Tangoed" gloves that are 1kV rated as well as mechanical safety & arc-flash, but usually it is leather over-gloves on insulted ones.

 

[SparkySy]

I have some 1k gloves with arc and mechanical protection too. I also have an arc and mechanical protection jacket and face shield. They definitely have their uses but it takes some dexterity to use tools with the gloves on!
Still wouldn't fancy touching that cut out though!

 

[telectrix]

wire brush, a British Racing Greeen aerosol, mask off the Crabtree badge, polish later. what's the problem?

 

[Lucien Nunes]

My usual offer applies here as I am still struggling to get a representative selection for the museum. If you can persuade them to leave it behind complete ./ unbroken for the price of a beer, I will refund the beer, your postage to send it to me and get you a beer for yourself!

 

[UNG]

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?

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.

To even suggest opening that service head is irresponsible and suggests that you would be tempted to do it.
The last time I saw a DNO guy open one of them just over 12 months ago he took a blowtorch to it to soften the pitch that was keeping the door from opening, he then warmed the pitch around the bottom of one of the fuses in an attempt to remove the fuses and when pulling it out it it totally crumbled, fortunately he had already put in a call for a jointing team to attend so it was all replaced and the earthing also fixed within a couple of hours

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.

I normally call the DNO when I find these problems as the householder generally doesn't understand or can explain the tech side
ENWL are normally very good and with something like that would be onsite in less than 2 hours

 

[partplonker]

To even suggest opening that service head is irresponsible and suggests that you would be tempted to do it.

You're absolutely right, it would be highly irresponsible to attempt opening it.

I find old gear really interesting and I apologise unreservedly if my curiosity and enthusiasm came across as encouragement to do something dangerous.

 

[Too_Wired]

To even suggest opening that service head is irresponsible and suggests that you would be tempted to do it.
The last time I saw a DNO guy open one of them just over 12 months ago he took a blowtorch to it to soften the pitch that was keeping the door from opening, he then warmed the pitch around the bottom of one of the fuses in an attempt to remove the fuses and when pulling it out it it totally crumbled, fortunately he had already put in a call for a jointing team to attend so it was all replaced and the earthing also fixed within a couple of hours

I normally call the DNO when I find these problems as the householder generally doesn't understand or can explain the tech side
ENWL are normally very good and with something like that would be onsite in less than 2 hours

That's great feedback, thank you I've contacted the landlord this morning and had a chat re. me speaking with the DNO tomorrow morning on their behalf.

 

[UNG]

That's great feedback, thank you I've contacted the landlord this morning and had a chat re. me speaking with the DNO tomorrow morning on their behalf.

If you have never seen the DNO change a service head and you have the opportunity and time to watch them do it it is well worth the experience.
The last one I got changed I was chatting with the 2 DNO guy's and was asked did I want to have a go they had already done most of it so it was at the not so dangerous part at that point. As well as swapping the service head they will swap the 951 earth clamp for constant force springs and a braid earth strap which is all part of the termination kit they use for re-terminating the cable. The instruction sheet in the termination kit gives a good explanation of how to terminate the cable and process involved and well worth a read, if asked the DNO guy's will let you have the sheet

 

[Too_Wired]

If you have never seen the DNO change a service head and you have the opportunity and time to watch them do it it is well worth the experience.
The last one I got changed I was chatting with the 2 DNO guy's and was asked did I want to have a go they had already done most of it so it was at the not so dangerous part at that point. As well as swapping the service head they will swap the 951 earth clamp for constant force springs and a braid earth strap which is all part of the termination kit they use for re-terminating the cable. The instruction sheet in the termination kit gives a good explanation of how to terminate the cable and process involved and well worth a read

I'll be there to view the change, like you say, purely to take the opportunity in gaining the experience of watching them do the job. I'll be taking the redundant hardware for my man cave too Anything of value such as instruction sheets for the termination kit will get borrowed... I'm sure they won't mind

 

[UNG]

I'll be there to view the change, like you say, purely to take the opportunity in gaining the experience of watching them do the job. I'll be taking the redundant hardware for my man cave too Anything of value such as instruction sheets for the termination kit will get borrowed... I'm sure they won't mind

The termination kit has pre cut pieces of heat shrink sleeve and all of it is very rarely used if asked they will give it to you and possibly get more bits out of the van from part used kits for you including the CF springs, earth braids, more shrink sleeving, I was swapping out the distribution equipment on one job and they left me with the seals for the service head rather than seal it so I could seal it when I had done my work

 

[SparkySy]

This is very true I have had bits from them in the past the constant pressure springs and braided earth are very useful! I have also had loads of the boxes from them for the resin joint kits, very handy for storage! They have let me keep the old cut outs in the past that they have replaced!

 

[Gavin John Hyde]

The dno will replace that. If its wpd tell them you want an ev charger fitted and they will definitely change it

 

[Deleted account]

Very true!

I should have made it clearer that I meant the overalls in addition to suitable gloves and a mask!

I have some "you have been Tangoed" gloves that are 1kV rated as well as mechanical safety & arc-flash, but usually it is leather over-gloves on insulted ones.

You have been tangoed gloves. Love it. My new name for them.

i always feel a bit wet and sweaty after using them.

sometimes my hands get sweaty also.

 

[partplonker]

I just came across this John Ward video of a similar supplier cutout. This one has asbestos, a fused neutral and rewireable fuses!

 

[pc1966]

I just came across this John Ward video of a similar supplier cutout. This one has asbestos, a fused neutral and rewireable fuses!

Interesting how they have both the asbestos separator, and the lid's sides coated to reduce the risk of an blowing fuse's arc migrating and making things far worse. I would be interesting to know the breaking limit of those fuses, as the BS3036 sort are only 1-4kA so often less than some region's would see at the cutout, but they don't have the asbestos tube and side containment, etc, seen here.

Having some compliant material between the ceramic holders and the base (the red rubbery stuff JW found holding it in place) makes sense so they don't get cracked by being too tight, either initial screwing up or due to thermal expansion. In the past I have used the red fibre washers on ceramic valve bases for the same reason!

 

[ipf]

wire brush, a British Racing Greeen aerosol, mask off the Crabtree badge, polish. what's the problem?

Always find a way round things, tel.....but no way is Crabtree from Poland...