What the hell is this main fuse?

[JohnS888]

Hi All

On a job this morning doing an EICR. As you will see from photos main live conductor showing signs of burning out at termination. Checked tightness of termination and main switch all seemed fine. I thought I would check main fuse rating to see rating of this. Supply is tncs with 16mm live conductors and 10mm main earth. On checking main fuse I come across what you can see in photo. A hollow round tube in fuse link terminals. This surely isn't legit? The fuse was sealed so I assume it was supplier that put it in

 

[ChipFanDave]

Maybe it was sealed by the same person who seal the consumer side of the isolator.

 

[Dustydazzler]

Looks like 20mm galv conduit

wonder what rating they put on the certificate

 

[snowhead]

The clue is the Red carrier.
That's a supply to a Flat / Apartment in a multi flat /appartment property.
All sourced from a single supply to the building.
Looks like an aluminium link.

 

[JohnS888]

Maybe it was sealed by the same person who seal the consumer side of the isolator.

So the presence of the isolator totally does away with need for the fuse? Thing is this is rated at 100 amps and pretty sure was 16mm main live and 10mm earth

 

[ChipFanDave]

So the presence of the isolator totally does away with need for the fuse? Thing is this is rated at 100 amps and pretty sure was 16mm main live and 10mm earth

Eh? Not sure what you mean by that.

 

[radiohead]

So the presence of the isolator totally does away with need for the fuse? Thing is this is rated at 100 amps and pretty sure was 16mm main live and 10mm earth

there will be fused protection at the building intake to each flat

 

[Julie.]

It's not a fuse it's a link!

This is fused upstream somewhere.

There will be an incomer to the property, at this point it will split into several fused supplies - one to each flat for example.

In the flat there will be a link - clearly marked as it will have a dark red / maroon coloured holder.

 

[DPG]

Wasnt there a similar thread the other day?

 

[westward10]

It was this one.

UK - Fuse link

Hi folks, Can anyone tell me more about a fuse link (I came across several in a communal cupboard today) . Was not expecting this and immediate thought was Bodget and Scarper had been here. Best described as a brass link similar to a piece of galv pipe inserted in place of a BS88..hence my concern!

www.electriciansforums.net

 

[snowhead]

And if you Google DNO cut out red fuse carrier within 0.36 of a second there are thousands of pictures and replies explaining what they are.

 

[Strima]

You need to find the main incomer to the building.

And be wary of pulling main fuses, this should be left to suitably trained and equipped persons.

 

[westward10]

No idea why you pulled that sealed link.

 

[pc1966]

No idea why you pulled that sealed link.

Judging by the photo of a burned conductor at the incoming switch I presume they were going to replace the cable & switch so needed it off?
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I guess curiosity resulted in them opening once out...

OK I should have read the text more carefully, no replacement just checked tightness. Doh!

 

[hasel5]

Why did you pull that link?
And that DB is a mess start in there and don't worry about a DNO cutout

 

[Julie.]

Judging by the photo of a burned conductor at the incoming switch I presume they were going to replace the cable & switch so needed it off?
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I guess curiosity resulted in them opening once out...

OK I should have read the text more carefully, no replacement just checked tightness. Doh!

There is an isolator between the meter and cu.

So no need to pull the link.

Edit

Also - the tails look too thin to me - single layer of insulation?

 

[pc1966]

What is odd is looking at the incoming switch as it shows no sign of thermal stress yet the cable is very unhappy. Do you think someone replaced a burned out switch and just left the wire like that?

 

[radiohead]

I would suggest the main switch in the DB has been replaced following a burnout, but not by a competent person as the isolator is not of the correct manufacture and the damaged conductor has not been rectified. It would be interesting to see how the busbar is connected given that the L and N connections are on the wrong sides
Edit post crossed with pc1966 who is clearly thinking the same

 

[Julie.]

What is odd is looking at the incoming switch as it shows no sign of thermal stress yet the cable is very unhappy. Do you think someone replaced a burned out switch and just left the wire like that?

Good point.

 

[pc1966]

It would be interesting to see how the busbar is connected given that the L and N connections are on the wrong sides

Well spotted, that also explains the neutral being nicked by the fixing screw post!
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Also - the tails look too thin to me - single layer of insulation?

Yes, another good point as no sign of a second sheath.

 

[Julie.]

Well spotted, that also explains the neutral being nicked by the fixing screw post!

Yeah that was a big giveaway to a poor installation !

Soo many things wrong there

 

[pc1966]

There is a special level of Fail here.

1. Not only did they use a different brand of replacement switch, but they managed to chose MK which (I think) are one of the few CU makers that have the switch on the left.
2. Then to compound it, instead of just swapping L & N designators on the switch they have fudged the neutral bar wire and busbar in some way to fit it in.
3. And let us not forget the burned live cable that has sufficient slack lower down to at least have had the worst 2cm or so removed and stripped back.

A photo showing the busbar at the incomer switch would be interesting!

 

[JohnS888]

There is a special level of Fail here.

1. Not only did they use a different brand of replacement switch, but they managed to chose MK which (I think) are one of the few CU makers that have the switch on the left.
2. Then to compound it, instead of just swapping L & N designators on the switch they have fudged the neutral bar wire and busbar in some way to fit it in.
3. And let us not forget the burned live cable that has sufficient slack lower down to at least have had the worst 2cm or so removed and stripped back.

A photo showing the busbar at the incomer switch would be interesting!

Unfortunately no pic of busbar PC. If upgraded tails to double insulated and swapped terminations over at main switch do you think this would bring installation upto satisfactory?

 

[westward10]

What is the rest of the installation like only you can answer that question.

 

[freddo]

I'd also want to at least fit the correct main switch, they aren't exactly expensive!!

CED / Axiom 100Amp DP Switch - MS Electrical Supplies

CED / Axiom 100Amp DP Switch - MS Electrical Supplies

www.mselectricals.co.uk

 

[JohnS888]

What is the rest of the installation like only you can answer that question.

The rest of it was ok in all honesty. Earthing good, bonding, complete rings, rcd protected. One thing that surprised me was no isolator for shower hardwired in. What's your take on that?

 

[pc1966]

Unfortunately no pic of busbar PC. If upgraded tails to double insulated and swapped terminations over at main switch do you think this would bring installation upto satisfactory?

As freddo says you can get the correct switch fairly cheaply so best to replace it and fit new double insulated tails (assuming no butchery of the busbar to make the MK one fit). The 19-strand flexible ones make life a who lot easier!

 

[davesparks]

On checking main fuse I come across what you can see in photo. A hollow round tube in fuse link terminals. This surely isn't legit? The fuse was sealed so I assume it was supplier that put it in

Red cutouts are disconnect links, not fuses.
They are also sealed and should not be removed by anyone other than a person authorised by the DNO or meter operator, the seal on that one has this clearly written on it!

 

[JohnS888]

I'd also want to at least fit the correct main switch, they aren't exactly expensive!!

CED / Axiom 100Amp DP Switch - MS Electrical Supplies

CED / Axiom 100Amp DP Switch - MS Electrical Supplies

www.mselectricals.co.uk

Top man Freddo thanks for that

 

[pc1966]

One thing that surprised me was no isolator for shower hardwired in. What's your take on that?

My initial reaction is that is wrong, there ought to be an accessible means of isolation, but off-hand I don't know if that is actually required.

Any idea why? Was there an old wall or pull switch that had been bypassed to save upgrading it to match current rating, or simply none ever fitted at all?

 

[davesparks]

One thing that surprised me was no isolator for shower hardwired in. What's your take on that?

What is your take on that? Do you think this is non-compliant with BS7671 and if so do you think it is something which affects safety and therfore needs to be coded?

As a person carrying out EICRs you obviously have a greater than average knowledge of the regulations.

 

[hasel5]

You are carrying out the EICR and should know what needs be done to bring the installation up to a condition to comply with when the regulations when installed

 

[ipf]

You are carrying out the EICR and should know what needs be done to bring the installation up to a condition to comply with when the regulations when installed

Any work now to current standards...18th.

 

[hasel5]

Agreed but only test and inspect to when installed

 

[JohnS888]

My initial reaction is that is wrong, there ought to be an accessible means of isolation, but off-hand I don't know if that is actually required.

Any idea why? Was there an old wall or pull switch that had been bypassed to save upgrading it to match current rating, or simply none ever fitted at all?

No, no signs of any pc. Think it was just initially hardwired without an isolator

 

[freddo]

Well at least it's one less thing to have burnt out terminals.

 

[radiohead]

Agreed but only test and inspect to when installed

Partly, but judgement needs to be applied. There are still plenty of (1970's) installations wired at a time when no RCD protection was installed even to external socket outlets. Lack of RCD protection to an external socket would now be a code 2.

 

[JohnS888]

What is your take on that? Do you think this is non-compliant with BS7671 and if so do you think it is something which affects safety and therfore needs to be coded?

As a person carrying out EICRs you obviously have a greater than average knowledge of the regulations.

My understanding of regs is that there is no actual regulation that specifies need for local isolation? The mcb is adequate to provide the isolation. Although that said shower should be installed to manufacturers instruction but as cannot gain access to this at the most I should note this on report but in terms of a regulation to back up a coding I am not aware of this. I may be wrong and hear others takes on it that is why I ask to be sure.

 

[radiohead]

My understanding of regs is that there is no actual regulation that specifies need for local isolation? The mcb is adequate to provide the isolation. Although that said shower should be installed to manufacturers instruction but as cannot gain access to this at the most I should note this on report but in terms of a regulation to back up a coding I am not aware of this. I may be wrong and hear others takes on it that is why I ask to be sure.

Note that not all MCB's are deemed adequate as a means of safe isolation for maintenance and repair, 3871's for example.

 

[davesparks]

Agreed but only test and inspect to when installed

No you don't, EICRs are carried out to the current edition of BS7671, as is made plainly clear in BS7671.

It is also made plainly clear that compliance with a previous edition of BS7671 does not necessarily mean that something should be recorded as an observation or altered. A lot of people misread or misunderstand the statement made, it clearly says 'not necessarily' but a lot of people incorrectly read it as 'does not'.
'not necessarily' means that it may or may not be non compliant, but that it cannot be judged as non compliant on the sole grounds of a change having been made to BS7671, it means that the item in question must affect safety or be of provable benefit to the installation to be recorded as an observation.

A good example is the change of conductor colours, red and black conductors do not comply with the current edition of BS7671 but this does not affect safety so there is nothing to report on.
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My understanding of regs is that there is no actual regulation that specifies need for local isolation? The mcb is adequate to provide the isolation. Although that said shower should be installed to manufacturers instruction but as cannot gain access to this at the most I should note this on report but in terms of a regulation to back up a coding I am not aware of this. I may be wrong and hear others takes on it that is why I ask to be sure.

That's my understanding too Regards local Isolators for a shower.

The installation must take account of manufacturers instructions, this was changed from 'must comply with' a few years ago as a lot of manufacturers instructions do not correctly reflect the requirements of bs7671 or were written based on older versions of it.