old rewireable fuseboxes

[telectrix]

hold your breath

 

[madmac]

Fire proof!:winkiss:

 

[telectrix]

asbestos ain't no problem as it takes at least 25 years for the damage to become apparent , so you get an old fart like me to remove it.

 

[1shortcircuit]

I took some pictures of an installation I spotted today. I was going to start a new thread but then I found this one whilst using the forum search function.

I hope the OP doesn't mind me adding this but it does sound like I have found an installation that was being described :thumbsup

As you should be able to see the tails come out of the meter and go straight into the new RCD Main Switch CU where tails then come out and go to the old rewire-able fuse-board.

 

[Engineer54]

What are the thought of the asbesdos in the fuse sheilds on the old porciline fuse ways i.e. MEM?

What about them??? Why would you need to touch the asbesdos flash sheilds in the first place??

There are guys on here, that would have you believe that pulling too many of those old fuses and your ''doomed'' to an early death. They don't want to listen, that these shields were made from the least harmful asbestos, and was in a form that made it less likely to become airborne. ...And that the amount in even a large fuse way board is Tiny. Plus there is rarely a need to touch or disturb the fuse shields.

If what these doom and gloom guys say had any validity to them ....i would have long since been gone!!! Training in a large industrial environment, i was exposed to far more of this stuff than most. We had a policy of replacing those shields every 5 years, section area by section area, whether they needed changing from flash damage or not!!! So as an apprentice, i've replaced literary thousands of the dammed things, ....And i might add, the shield came on a roll, so that it had to be cut to size to fit the carrier...


All you really need to stay safe when pulling rewirable fuses with asbestos flash shields, is basic ''commonsense'' !!! ..... Or as Telectrix suggested, ...get an old geezer to pull erm !!!

 

[tawraste]

no problem at all mate, keep them coming!

bit different from what i saw though. my one had the rcd after the main cu, but simply linked on to the rails with 10mm t&e. not even tails.

in your example i think they were trying to provide rcd protection for the whole install perhaps? blatantly contravening 415.1.2.

would that install be ok if it had been an rcbo rated below 60A?

edit: bearing in mind 415.1.2, how can wylex manufacture this unit with 'main switch' printed on it?

edit: whilst 415.1.2 is relevant i should have mentioned section 314 too!

 

[malcolmsanford]

Tawraste I/m not sure what your post is menaing mate.

415.1.2 alluded to having overload protection and the Bs 3036 fuses will give you that. I think your trying to evoke reg 314.1 division of the installation.

The RCD may have been fitted prior to the 17th edition in 2008 and so then not contravening any regs. It may have been fitted to the BS 7671-2008 because the system is TN-S and it may have an High Ze value because of cables being change/upgraded exterior to the installation. It may even be a converted TN-S to a TT and therefore needed 30mA protection.

What do you do if the customer didn't want the expense of a board change, you have to deal with the situation at hand, and by fitting an upfront RCD, though not a perfect solution, it does leave the installation safer.

 

[tawraste]

thanks malcolm, just after my post i remembered 314 and noticed my mistake. i was searching for reference to a rcd not being used as a main switch.

in the case of the customer in your example yes, it's definately safer - so would you then put that down as a departure form 314?

 

[malcolmsanford]

on a PIR or a EIC ?

On a PIR then no code for me, as the RCD may have been fitted under the 16th regulations. I may put a cover letter to the report advising the client of the drawbacks on this.

On an EIC I would most likely make a note of it under existing installation .

 

[tawraste]

cool, thanks again! things like this are great for getting the regs straight in my head. reading them every day and still finding more understanding is constantly required!

 

[malcolmsanford]

cool, thanks again! things like this are great for getting the regs straight in my head. reading them every day and still finding more understanding is constantly required!

well if it is any consolation i've been reading the Regs from the 14yh edition and I'm still baffled by many of them

 

[1shortcircuit]

The RCD may have been fitted prior to the 17th edition in 2008 and so then not contravening any regs.

This RCD unit was only fitted last month, month before max. I believe it was done when the boiler was upgraded?

I think it was TNC-S, I'll see if I can pop back and take another peek.

I understand the part about leaving it in a safer condition it just looked a little odd having this setup.

I'm wondering if perhaps the old boiler is on a spur on the sockets and therefore had to have RCD protection installed before the new boiler could be commissioned?

 

[malcolmsanford]

I agree it does look odd, and whoever fitted it must have assessed if leaving the installation protected by a single 30mA RCD, and therefore safer, out weighed 314.1 and division of installation.

Without all the relevant facts, like Zs values for the circuits, etc it's difficult to assess the reasons for it, I have to be honest it would be perhaps the last way I would have done it.

 

[1shortcircuit]

I agree it does look odd, and whoever fitted it must have assessed if leaving the installation protected by a single 30mA RCD, and therefore safer, out weighed 314.1 and division of installation.

Without all the relevant facts, like Zs values for the circuits, etc it's difficult to assess the reasons for it, I have to be honest it would be perhaps the last way I would have done it.

Can I just run a scenario past you please?

"IF" future work was requested on this installation (Let's say an additional double socket on the downstairs ring) that no further protection would be required as the Mains Bonding is up to current regs and the Installation is protected by 30Ma RCD?

This installation is in a home owned by an elderly couple. I believe the Boiler was upgraded because they pay a small amount every year into some kind of scheme that helps them with GAS/Electric repairs? I'll try to find out more :thumbsup

 

[malcolmsanford]

Yes all future work on the installation will be 30mA RCD covered.

I have to admit that knowing that the owners of the house are an elderly couple makes the use of an upfront RCD protecting the whole insulation even more of a surprise.

How was the boiler wired, was it spurred of an existing ring final? The thing is it seems the job had been done by one of these government type scrapage schemes.

What I would have most likely done was if the boiler was spurred of the ring final. then I would have fitted an RCD for that, that way you would at least provide RCD protection to all the sockets on that circuit.

It is an hard call as we said on one hand they have left the installation safer with RCD protection, on the other you could get the situation of the whole installation tripping out leaving a vulnerable couple without power.

 

[1shortcircuit]

How was the boiler wired, was it spurred of an existing ring final?

I'm pretty sure it's spurred from the downstairs ring although I haven't checked to see for sure. I just don't recall see a dedicated circuit for it though?

on the other you could get the situation of the whole installation tripping out leaving a vulnerable couple without power.

Luckily enough they have umpteen family members close by that would drop everything and get to them as quickly as possible if needed... yes, they do have a mobile phone lol

Whilst they are elderly, they are still able and always active. It's another one of those situations though where they have lived in the same house for decades.

What I would have most likely done was if the boiler was spurred of the ring final. then I would have fitted an RCD for that, that way you would at least provide RCD protection to all the sockets on that circuit.

This is exactly how I would have expected so see it done and how I would have tackled the situation myself. :thumbsup

Thanks for your help malcolmsanford, this thread has been of great use to me.

Thanks tawraste, I'm glad I found your thread before creating my own:thumbsup

 

[1shortcircuit]

I agree it does look odd, and whoever fitted it must have assessed if leaving the installation protected by a single 30mA RCD, and therefore safer, out weighed 314.1 and division of installation.

Without all the relevant facts, like Zs values for the circuits, etc it's difficult to assess the reasons for it, I have to be honest it would be perhaps the last way I would have done it.

Hope nobody minds me continuing this :thumbsup

I manage to lay my hands on a few further details this afternoon

The home uses a TT system, 1362 Protective device supplying 3036 board.

IR Test results were recorded as

170 Mohms LN
170 " " LE
170 " " NE
170 " " L/N/E

Earth Fault Loop Impedance 17.5 Ohms

RCD Trip times 10/18 ms


The boiler is indeed spurred from the ring and there is also an additional note :-

"Recommend Fuse Board Upgrade"