old fashioned Fuse-boards

thedigger · 7 Jan 2009

Hi all... sorry to drag up an old post, but this page came up in a Google search.

I've also got one of the old fashioned Fuse-boards (with actual fuse-wire in the cartridges etc). I currently have 5 circuits - 2 x 5A lighting rings, 2 x 20A mains and 1 x 15A immersion heater (from memory). My plan is to swap these over with MCBs, because MCBs are safer and more sensitive (right?), and it's far easier to trip a switch than rewiring a fuse. I just have two questions

Is a 6a MCB a straight swap for a 5a fuse (or do I need to find a 5a MCB?)

And is this a job that must be done by a professional, or does it just have to be done by a "competent person" (which I class myself as

)

Cheers!

adwt2004 · 7 Jan 2009

It's a 6amp mcb. Common for lighting. If i was doing it i would do this myself with the CU main switch off. But suspect others will think an electrician should do it.

Up to you really and whether you're competent enough to do it.

ban-all-sheds · 7 Jan 2009

It's notifiable, don't forget....

thedigger · 7 Jan 2009

ban-all-sheds said:
It's notifiable, don't forget....

To who? Does that mean a sparky needs to verify the work?

ban-all-sheds · 7 Jan 2009

thedigger said:
To who?

Your Local Authority's Building Control dept.

In advance if you do it.

Does that mean a sparky needs to verify the work?

It's not as simple as that:

//www.diynot.com/wiki/electrics:part-p

thedigger · 7 Jan 2009

Cheers b-a-s - just check the part P regs, and it says you must notify the Building Control dept for:

# New consumer unit

Does replacing the individual fuses for MCBs count as installation of a new CU?

ban-all-sheds · 7 Jan 2009

Dunno what you were reading, but the actual Building Regs are here: http://www.planningportal.gov.uk/uploads/br/BC_Consolidated_Bldg_Regs.pdf

Anything not listed in Schedule 2B is notifiable, and swapping protective devices is not listed in Schedule 2B.....

kkynaston · 7 Jan 2009

You will be changing the charteristics of a circuit which is notifiable.
As you will be changing the overcurrent device the tripping times may be different so this needs to be tested and notified to your local BC before work starts if you do it yourself.

I have a guess that you have no RCD protection and bonding is probably inadequate.

Best thing to do is get a PIR done, well worth the money. It will highlight all the areas of your electrical system that are in need of attention.

Can you take a pic of your fuseboard and meter area, it might give us a clue to the age of the installation.

thedigger · 7 Jan 2009

Cheers guys

The house was built circa 1970, looks like the same as this CU from the hall of shame:

I can post another photo later if needed though?

FYI, these are the MCBs I was going to use:

dingbat · 7 Jan 2009

That fuseboard photograph has been posted here before, some years ago...

...as an example of how not to terminate armoured cable. And provoked a discussion regarding doubling up of live conductors, amongst other things.

You sure this isn't a wind up?

flameport · 7 Jan 2009

thedigger said:
because MCBs are safer and more sensitive

The MCB will operate quicker than a fuse. Thats it.
MCBs are not safer than fuses. Both the fuse and MCB will cut off the supply in the event of a fault or overload.
Neither of them provide any protection against electric shock.

The only other 'benefit' from replacing rewireable fuses with MCBs is that they can be reset more easily. However, fuses should not need replacing often, if at all. If fuses are blowing often, you have other serious problems which need to be fixed.

You would be better putting the money towards a new consumer unit, rather than buying those plug in MCBs.

thedigger · 7 Jan 2009

dingbat said:
That fuseboard photograph has been posted here before, some years ago...

...as an example of how not to terminate armoured cable. And provoked a discussion regarding doubling up of live conductors, amongst other things.

You sure this isn't a wind up?

It's not my CU, it's a picture from the hall of shame - My CU looks exactly the same though.

Flameport - it's not blowing regularly, I just don't like pulling the switches when doing maintenance (like replacing sockets, switches etc) as you get a fairly sizeable crack and flash when the fuses are reconnected live - and it's a royal pain in the arse having to turn the whole power off.

Taylortwocities · 7 Jan 2009

thedigger said:
as you get a fairly sizeable crack and flash when the fuses are reconnected live - and it's a royal pain in the a**e having to turn the whole power off.

Well you are a very large burke then. The instructions say very clearly that you must turn off the main switch before handing the fuses.
The instructions are there for a very good reason.

Can you imagine why??

ban-all-sheds · 7 Jan 2009

How often do you go round replacing sockets and switches?

thedigger · 7 Jan 2009

...which is why I want to swap for RCBs? They're more convenient as I don't have to switch the power off to do basic tasks.

My intention is to turn the power off one more time - fit RCBs in place of the Fuses and power up.

I will need to notify the local Building Regs before doing it, that's what I wanted to know

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old fashioned Fuse-boards

kkynaston

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