6mm pyro...

[ETradesmen]

Hello everybody, my name is Michael.

Last week a landlord called me regarding a faulty electric shower that the company tried to re fit under warranty but told him that the cable supplying it was under rated so they couldn't finish the job...

I went to take a look and the property being a hostel type flat in London did not meet 17th edition regulations. There was no RCD present and the consumer unit was older than me (27 years). I looked at the circuit supplying the shower and it was a 6mm twin and earth on a 50amp breaker. This obviously isn't correct as the run was over 15M and the shower was 9.5KW.

Obviously a shower pulling 38amps cannot be fed via a 6mm twin and earth on a 50amp breaker unless you were after an insurance job...

So after wrestling the metal cabinet off the Crabtree fuse board I noticed it was fed via a 6mm pyro. The circuits in the board were a cooker supply, upstairs lights, downstairs lights, immersion, upstairs sockets, downstairs sockets and a shower supply... Is the 6mm pyro capable of such demand?

I couldn't gain access to the meter cupboard to see what the fuse was feeding the flat, but to me it sounds a bit under rated?

The length of run is around 30M and the cable is clipped direct...

Obviously the landlord is asking me why it needs changing if 'its worked perfectly fine all this time'. But I don't really fancy putting my name on a job if I think it's going to be on the ITV headlines the next day.

Your views are welcome.

Michael > NICEIC registered > 10 years in the business

 

[Des 56]

I'm afraid i've had to use side cutters and long nose pliers on more than a few occasions in the past, it's no big deal really!! ....Unless you try to strip it like you would a PVC cable!! lol!!

That was the point I was making I could happily strip away with a pair of cutters and make an end off before others have set up their stripping tool and blunt blades. poaaibly mangling the sheath in the process

Using side cutters as you know has a knack to it
It can be a laugh a minute, watching someone try it who is not used to doing so
Those who have worked with pyro can also use the tools or improvise with whatever is at hand,the skill of the person can sometmes be judged when the cutters come out

 

[Engineer54]

haha!!! OK i'm with you now Des!! ...Just wiping the sleep out of my eyes, ...i should be ok after my second coffee!! lol!!

 

[wade88]

Well different cable types aside, wont be long before this takes off.

Wireless Power May Cut the Cord for Plug-In Devices, Including Cars

 

[Engineer54]

I've never had to use pyro but I might buy a few meters to have a play with,
regarding E54s post I'm guessing your using the long nose pliers to open it, like youd open a tin of corned beef?

That's about the size of it Yes!! just don't use the short flimsy long nose pliers, mine are like a Mechanic's, with a nose about 6 to 7'' long. Always better to make your own emergency stripping bar whenever possible, it's a much easier and faster task then, especially if your terminating into a panel or CU etc... lol!!

Like many of the others here, that have extensive experience of working with MICC, i can terminate and make off the pot end without any of the specialised tools normally required/associated with terminating MICC... lol!!

 

[Engineer54]

Well different cable types aside, wont be long before this takes off.

Wireless Power May Cut the Cord for Plug-In Devices, Including Cars

Tesla had a viable system for drawing power wireless!! That idea was soon purposely lost in the file 13 achieves by the power industry of the time!! lol!!

 

[shanky887614]

done all college courses and never touched anything bar singles and t+e

except swa on 2 occations

1 was test day.


havent so much as looked at a piece of mims till i left college

 

[Stroppy]

Made a start on my MIMS task at college today. I am no longer a MIMS virgin!

 

[TAZ]

I remember the first time as an apprentice making off my first pyro with the electrician watching closely. We had to make a stripping bar out of mild steel at college. having got the end started with the side cutters & then using the stripping bar (yes i did cut a foot or so off before stripping) I stripped it down to the required length & proceeded to screw on the pot by hand & then using footprints to tighten it fully,( & checking for that naughty little swarfe ring inside the pot & then blowing inside the pot to clear out the magnesium oxide powder that was when all hell let loose & made to look a complete idiot . oh well happy days.

 

[ipf]

Mims....are you taking the Micc?

 

[TAZ]

As an aside copper itself tends to work harden over the years & getting the pots & seals as well as the glands for imperial sizes as used in the sixties in flats with concrete ceilings would be very difficult to get these days. If one of the conductors breaks of from the pot, whilst trying to manipulate it it becomes a real headache to deal with or if the outer sheath gets damaged the hygroscopic magnesium oxide will begin to absorb mosture & eventually will start to cause problems. Just not worth the hassell

 

[UNG]

You could always check this data sheet for conversion options for imperial pyro using metric seals

Don't know if they still do it but when Pyro was owned by BICC you could call the sales office and they would arrange for a pot to be drilled suit the imperial size you needed usually within 24 hours

 

[accordfire]

You could always check this data sheet for conversion options for imperial pyro using metric seals

Don't know if they still do it but when Pyro was owned by BICC you could call the sales office and they would arrange for a pot to be drilled suit the imperial size you needed usually within 24 hours

Not heard of that for a long time now. Standard "conversion" now is a potted junction, and new cable from that to the termination. On fire anyhow, though on certain LV jobs, I've been asked to re-run the whole cable.

And yes others - the joys of pyro, or MICC - though what on earth MIMS is, is anyone's guess - Mummy's Insulated Milk System possibly?

As for the joys of wet pyro. Oh boy. Days (and nights) of fun! You very quickly learned to improvise on tools too - especially at 40 floors up from your main tool box.

 

[Engineer54]

Mineral Insulated Metal Sheath, the term is used to cover both copper and aluminium cables...

 

[accordfire]

Mineral Insulated Metal Sheath, the term is used to cover both copper and aluminium cables...

Well, now you put it like that.... I'd still far sooner work on Mummy's Insulated Milk System.....

Yes, it makes sense as such, I don't honestly think I've ever heard it described as such though - only as MICC or Pyro.

The aluminium is interesting - I thought we'd long done away with aluminium as a conductor for a number of reasons, and to my understanding, FP200 and similar cables which have an aluminium sheath don't qualify as MICC or MIMS...as they're not mineral insulated....

Time for me to do a little more reading up I think.

 

[Engineer54]

Well, now you put it like that.... I'd still far sooner work on Mummy's Insulated Milk System.....

Yes, it makes sense as such, I don't honestly think I've ever heard it described as such though - only as MICC or Pyro.

The aluminium is interesting - I thought we'd long done away with aluminium as a conductor for a number of reasons, and to my understanding, FP200 and similar cables which have an aluminium sheath don't qualify as MICC or MIMS...as they're not mineral insulated....

Time for me to do a little more reading up I think.

They made Pyro in both copper and alluminum, probably still do to some extent. I haven't seen it about for a number of years now though...

EDIT... You'll find that alluminium is still used as a conductor by the DNO's in virtually all of there distribution cables, including the bare overheads etc.... You'll also find a good deal of it in (multi-core distribution cables) being used in industry too...