Boiler circuit 16A MCB

[Michaelwgroves]

That still won't stop the spread of fire!

Fire retardent does not mean the same thing as fire proof!

So how would you prevent the spread of fire for a knockout?

 

[davesparks]

I'd not thought about, Selectivity, this is a good point. Saving myself doing the maths, what size MCB do you put on boiler circuit to achieve selectivity?

I would install a 16A 2.5mm radial by default.

 

[davesparks]

So how would you prevent the spread of fire for a knockout?

If it ever becomes a requirement of the regulations I will worry about it then.

Currently any fire sealing that is needed on a job I would get a specialist fire sealing contractor in to deal with it.

 

[loz2754]

I agree with your comments, but what is fine wire and very fine wire ?

Have a look at these:

ferrules - how to use, tips and colour codes

German and French ferrule crimp colour codes, how to use ferrules and where to use ferrules. Handy ferrule downloads and electrical tutorial videos.

www.efixx.co.uk

 

[Lucien Nunes]

I'm now curious on the definition of fine wire & very fine wire.

Generally copper conductors will be stranded to one of a number of classes within IEC 60228.
Class 1 = solid conductor.
Class 2 = stranded conductor (e.g. larger T+E, normal 6491x conduit cables) for which terminals in electrical fittings are normally suitable without ferrules or other treatment.
Class 5 = fine stranded / flexible and Class 6 = very fine stranded / highly flexible (e.g. tri-rated BS6231, BS6500 flexibles) may require ferrules or similar treatment when used with terminals that are not designed for class 5/6 conductors.

Post crossed with @loz2754

 

[timhoward]

I'd not thought about, Selectivity, this is a good point. Saving myself doing the maths, what size MCB do you put on boiler circuit to achieve selectivity?

My hunch was a B16.... and I was curious enough to do a bit of scribbling. This is a BS1362 3A fuse time/current curve roughly superimposed onto the type B MCB graph:

Without more accurate manufacturer's let-through data of the device in question, the lowest MCB that I would bet my supper on not tripping before the fuse is in fact a B16. A B10 is probably too close to call!

 

[Michaelwgroves]

My hunch was a B16.... and I was curious enough to do a bit of scribbling. This is a BS1362 3A fuse time/current curve roughly superimposed onto the type B MCB graph:
View attachment 107210
Without more accurate manufacturer's let-through data of the device in question, the lowest MCB that I would bet my supper on not tripping before the fuse is in fact a B16. A B10 is probably too close to call!

Excellent post, thanks for taking the time to put this together

 

[Michaelwgroves]

Have a look at these:

ferrules - how to use, tips and colour codes

German and French ferrule crimp colour codes, how to use ferrules and where to use ferrules. Handy ferrule downloads and electrical tutorial videos.

www.efixx.co.uk

Thanks mate, really good link. Learnt a bit about flexible cables.

 

[ERFspark]

Respectfully - if you don't know and understand what you're inspecting, should you be inspecting?

Could not agree more
A painful read that

 

[Michaelwgroves]

If it ever becomes a requirement of the regulations I will worry about it then.

Currently any fire sealing that is needed on a job I would get a specialist fire sealing contractor in to deal with it.

I would argue it is a requirement from 17th edition.
Guidance Note 4 (17th Edition) - Protection Against Fire advises
3.8.1 Consumer Units & Similar Assemblies in domestic premises
'The Installer must seal all openings into the non-combustible enclosure or cabinet for cables, conduits, trunking or ducting that remain after the installation of cables. Good workmanship and proper materials must be used and account must be taken of the manufacturer's relevant instructions, if any.'

I was pulled up on this by Stroma during an assessment.

I've not had a good reason to get latest Guidance Note 4 until now, so just ordered 18th edition A2. It arrives tomorrow. I'll give a further update once it arrives, unless someone beats me to it.

 

[Michaelwgroves]

Could not agree more
A painful read that

That would apply to every question on this forum. You mistake the spirit of forums, it's not a place to put others down, to make yourself feel superior. Your comments say more about you. Maybe take a look in the mirror.............
Interestingly, those that criticised, did not put forward any suggestions, just comments of I am holier-than-thou..............
I think Napit & NICEIC are better placed to determine competence.

 

[loz2754]

Napit & NICEIC are better placed to determine competence

One would like to believe so. But there's competence to install, and another level of competence to inspect and test.
Many joined the competent persons schemes solely so they could self certify notifiable works, works that they had installed themselves, not realising that this scheme membership did not cover their competence to do periodic inspection and testing. It was even written into the NICEIC Domestic Installer rules that they would not be allowed to carry out EICRs under the NICEIC banner or use their logo on such EICRs.
It wasn't until the PRS 2020 regulations came into being that the NICEIC started to allow Domestic Installers to do EICRs, but required them to undergo another assessment to determine their competence to do EICRs.

 

[Michaelwgroves]

One would like to believe so. But there's competence to install, and another level of competence to inspect and test.
Many joined the competent persons schemes solely so they could self certify notifiable works, works that they had installed themselves, not realising that this scheme membership did not cover their competence to do periodic inspection and testing. It was even written into the NICEIC Domestic Installer rules that they would not be allowed to carry out EICRs under the NICEIC banner or use their logo on such EICRs.
It wasn't until the PRS 2020 regulations came into being that the NICEIC started to allow Domestic Installers to do EICRs, but required them to undergo another assessment to determine their competence to do EICRs.

I've no experience with NICEIC, I recall Stroma having two competencies, but for sure, my Napit includes EICR's.

 

[ERFspark]

One would like to believe so. But there's competence to install, and another level of competence to inspect and test.
Many joined the competent persons schemes solely so they could self certify notifiable works, works that they had installed themselves, not realising that this scheme membership did not cover their competence to do periodic inspection and testing. It was even written into the NICEIC Domestic Installer rules that they would not be allowed to carry out EICRs under the NICEIC banner or use their logo on such EICRs.
It wasn't until the PRS 2020 regulations came into being that the NICEIC started to allow Domestic Installers to do EICRs, but required them to undergo another assessment to determine their competence to do EICRs.

I don’t do domestic as I’m industrial. Does that mean they don’t have to do the 2391 qualification?

 

[Michaelwgroves]

I don’t do domestic as I’m industrial. Does that mean they don’t have to do the 2391 qualification?

Test & Inspect was required for my CPS with Napit, and previously for Stroma.

 

[loz2754]

I don’t do domestic as I’m industrial. Does that mean they don’t have to do the 2391 qualification?

No, to join the scheme they need a 2391 qualification

 

[ERFspark]

No, to join the scheme they need a 2391 qualification

Excellent

 

[Rockingit]

I would argue it is a requirement from 17th edition.
Guidance Note 4 (17th Edition) - Protection Against Fire advises
3.8.1 Consumer Units & Similar Assemblies in domestic premises
'The Installer must seal all openings into the non-combustible enclosure or cabinet for cables, conduits, trunking or ducting that remain after the installation of cables. Good workmanship and proper materials must be used and account must be taken of the manufacturer's relevant instructions, if any.'

I was pulled up on this by Stroma during an assessment.

I've not had a good reason to get latest Guidance Note 4 until now, so just ordered 18th edition A2. It arrives tomorrow. I'll give a further update once it arrives, unless someone beats me to it.

That's talking about enclosures, not fire compartments in structures. If someone from Stroma was making an argument over it then I'd suggest they may have been misguided.

 

[timhoward]

That's talking about enclosures, not fire compartments in structures. If someone from Stroma was making an argument over it then I'd suggest they may have been misguided.

I think this was originally about a missing grommet in a consumer unit and a suggestion this was a fire safety issue.

Were Stroma talking about the IP rating being compromised or suggesting that the consumer unit has to be a perfectly air-tight enclosure?
Obviously gaping holes are not a good thing but my higher concern on an EICR is "can someone access live parts? (C1)" or "can someone access a single insulated cable (C2)"

 

[Michaelwgroves]

That's talking about enclosures, not fire compartments in structures. If someone from Stroma was making an argument over it then I'd suggest they may have been misguided.

Yes, we are talking about enclosures.
If you make a hole in an enclosure, how do you make that hole comply. In this thread we are talking about 32mm knockout.
In my stroma assessment, it was 6" knockout in back of consumer unit.
However, both holes give open into cavity, which would allow fire to travel through the cavity.