Micc tails from meter cupboard

[TheCodboy]

Hi all,been to look at flat today and it requires a new Consumer unit. Its an old porcelain type of fuse holder and shield and some of them are damaged. The flat is in one of these 60's built blocks with a meter cupboard on each floor. In the meter cupboard is the service head, meter and an isolator. From the isolator is a 6mm 2 core pyro leading to the flat. The main earth is taken from an earth clamp on the pyro pot,looks to be 2.5mm There is absolutely no sign of overloading, heat or anything like that. My MFT is being calibrated at the moment so i couldn't take any readings,but i did do a visual check in the board and at sockets etc and as i say, no sign of thermal/overload trouble. 2 bed flat with a small kitchen so don't think there's a great deal of load. So, realistically there's no way of upgrading the tails, would you guys be happy to install a new DB with these tails? I'm going to ring Napit tomorrow, but i would like to hear what you guys have to say. Many thanks.

 

[R-fur]

Is the isolator fused, what length is the pyro?

 

[telectrix]

if that MICC tests OK, and is adequate for the load, no reason not to use it

 

[TheCodboy]

Is the isolator fused, what length is the pyro?

It doesn't appear to be fused. From the meter cupboard roughly 6 meters give or take.
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if that MICC tests OK, and is adequate for the load, no reason not to use it

My thinking is that i can only improve the condition of the install by adding rcd protection etc. The service head fuse carried says 60/40a I know that its whats inside that counts but there's a good chance that hasn't been touched since day 1.

 

[R-fur]

If its more than three meters it should be fused. Are the earth connections to the pyro OK? I tend to agree with Tel that if it tests ok it will be fine. but it should be fused and the earth needs to be checked.
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Pyro has an earthed sheath and dosent necessarily require an RCD.

 

[Dave OCD]

I wouldn't be surprised [without looking it up] if 6mm MICC is capable of carrying 50 amps.

 

[TheCodboy]

I wouldn't be surprised [without looking it up] if 6mm MICC is capable of carrying 50 amps.

57a and the outer sheath equivalent of roughly 16mm earth. ??

 

[Lucien Nunes]

But only 51A if bare, exposed, clipped direct, because the circumference is smaller so less surface area in contact with the air.

However, you mention a 1960s build date, in which case it's surprising that the cable is metric. Does it actually say 2H6?

 

[TheCodboy]

But only 51A if bare, exposed, clipped direct, because the circumference is smaller so less surface area in contact with the air.

However, you mention a 1960s build date, in which case it's surprising that the cable is metric. Does it actually say 2H6?

It says 6mm on the cores

 

[davesparks]

It says 6mm on the cores

That doesn't necessarily mean much, check the markings on the gland or pot.
I've seen 6mm stub sleeve used 1.5mm before.
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Yes I wouldn't hesitate to use MICC as long as it is in acceptable condition.

I wouldnt accept a BS951 clamp as the means of connecting to the sheath for a CPC though, they aren't designed for that purpose.

In the past I have dealt with this situation by wrapping a copper strip around the cleaned sheath with a tab sticking out and soldering it in place, then bolting a lug to the copper strip.

 

[TheCodboy]

But only 51A if bare, exposed, clipped direct, because the circumference is smaller so less surface area in contact with the air.

However, you mention a 1960s build date, in which case it's surprising that the cable is metric. Does it actually say 2H6?

2h6 on the pot

 

[davesparks]

Here's one I did a few years ago, (with the correct permissions from the BNO) moved and reterminated an imperial 2 core feed to a flat.
As per pyrotenax's advice the nearest size metric pot was soldered onto the cable. I made the earth connection and the clips from copper strip (I keep stuff like that in one of my toolboxes as I often seem to end up dealing with such things)


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View attachment 59342
2h6 on the pot

Those couplers with the earth terminal are a rare beast these days, and when you do find them they are not so substantially made anymore!

So it is indeed metric cable, that puts the date of the installation later than the 60's as metric cable came in in the early 70's