Pyro Cabling?

[Snapester]

Hi guys, i did some work on a flat just over a year ago and tested and did a PIR which i passed as good condition after the remedial work!
Tenants in the flat having issue with cooker circuit in which the property maintenance guy came to have a look at, to which he said needs a full rewire and pyro should not be used anymore! Go figure do any other sparky folk feel this way? I believe Pyro is one of the most bullet proof installations available?
Cheers

 

[Risteard]

I think that bare unsheathed pyro buried in cement could be a problem with the copper being attacked by whatever is in the cement.

Just to be pernickety it's oversheathed rather than sheathed as the copper cover is the sheath, hence the name MIMS (Mineral Insulated Metal Sheathed).

 

[Engineer54]

Just to be pernickety it's oversheathed rather than sheathed as the copper cover is the sheath, hence the name MIMS (Mineral Insulated Metal Sheathed).

MIMS is a relatively later name given to MICC/Pyro, I don't know but maybe given, when they started using Aluminum as well as copper. There was also a copper alloy sheathed cable, but i don't think it lasted too long...

 

[ipf]

yes IPF BICC made pyro made near me in prescot, brilliant to see it made starts out as a short fat roll and gets drawn out thinner and thinner till they get the right size,as someone mentioned about college my last apprentice was in college one day and after being shown how to do something he said he preferred the way I had show him,he showed the teacher my way and the teacher said blimey it must be an old bloke training you son, I havent seen that done in a good while.So its official then at 47 i,m an old bloke,must have done something right though cause he came out best in his class.

First worked on the stuff when you were about seven years old then. But I certainly don't consider myself in the 'old' category.lol!!

 

[Top Cat]

He's probably only saying that because he was useless at making it off and dressing it properly when he was a spark in the real world

But was he a spark in the real world?

Remember the saying:-

Those that can, do.

Those that can't teach!

 

[Andy78]

I, sadly have not had the chance to do much pyro work in my career so far. When I have though I have thoroughly enjoyed it. The satisfaction of a well installed length of pyro really is worthwhile the effort involved. Love going along and tapping out the impeferctions with a plastic hammer to get it dead straight !
People that say it has no place in modern installations are off their head. I do agree that inside buildings for fire alarms, FP200 is cheaper, faster to install, and easier to work with. It's hard to justify the cost of pyro in this instance. But for places that require mechanical protection you can't beat it. It's surely a faster install than metal conduit systems for exterior purposes.
At college I was also shown the anvil test. It got hammered out to 3 times its original width before the lamp wouldn't light. Most impressive !

 

[UNG]

People that say it has no place in modern installations are off their head. I do agree that inside buildings for fire alarms, FP200 is cheaper, faster to install, and easier to work with. It's hard to justify the cost of pyro in this instance. But for places that require mechanical protection you can't beat it. It's surely a faster install than metal conduit systems for exterior purposes.

It's only faster to install because it is very rarely installed properly with metal P clips or metal ratchet ties. The manufacturers guidance / requirements when clipping and fixing FP or it's derivatives is invariably not followed when it is being installed. The number of times I've seen it installed in PVC mini trunking with no metal clips to hold it if the trunking melts and the same goes for PVC conduit or under slung on tray with nylon ratchet ties holding it or even fixed using knock on clips in my opinion it is the most mis-installed cable ever used on site especially when it is used for safety circuits.

Despite the cost of Pyro for the reasons above what price do you put on safety or a life or two it just a pity other people don't take that view. While FP installed correctly can perform and meet the requirements it will always be the Mini Metro while Pyro will be the Rolls Royce of cable

 

[Guest111]

First worked on the stuff when you were about seven years old then. But I certainly don't consider myself in the 'old' category.lol!!

I dont consider myself old either,just had a good sparks who taught me a lot of the old ways,think the lads teacher was peed off that I was teaching him that there are more ways to do a job than the one way they teach in college.

 

[ipf]

Fair enough. Goes to show how invaluable an apprenticeship is. We know how important qualifications are, but if you can't put things into practice what's the point. Better hold off a bit now, straying off the point and getting into other areas......

 

[GLENNSPARK]

Being a year out of college I can 100% certain guarantee that we were not shown how to pot Pyro because and I quote the head of department of my college "It is outdated and you should be using FP200" the closet we got to Pyro was our tutor hitting it with a hammer to demonstrate its indestructibility of the cable after calling the head of apartment several curse words for saying pyro is outdated and it is better to use FP200,
Unfortunately I have no experience with Pyro and would love to learn how to work with it, its due to the course requirements I did do a course with C&G but was not taught Pyro.

"its outdated and you should be using fp200"......surely this lecturer should see that you use the most appropriate cable/s for the installation/environment...including pyro......so what he was saying was a load of crap.......

 

[ackbarthestar]

lol,
once ive made the ends off ill meggar it out !

Interesting, I was once shown how to IR test the MI one end at a time because if it goes down at one end after you have made off the other you will have a 50% chance of choosing the right (wrong) end to take apart.

To be more explicit, sometimes when cutting the thread with the pot/wrench a very small slither of copper, unseen by the eye can get caught and when filled and crimped the copper slither shorts across the conductors. I know it happened to me once when putting in a fire alarm system in a school and needed help to find the fault. The faulted end was subsequently burned out with a IR test set at 1000V

When installed properly it will last for years, the problem comes when other sparks mess around with it once in place.

 

[mackers]

Interesting, I was once shown how to IR test the MI one end at a time because if it goes down at one end after you have made off the other you will have a 50% chance of choosing the right (wrong) end to take apart.

To be more explicit, sometimes when cutting the thread with the pot/wrench a very small slither of copper, unseen by the eye can get caught and when filled and crimped the copper slither shorts across the conductors. I know it happened to me once when putting in a fire alarm system in a school and needed help to find the fault. The faulted end was subsequently burned out with a IR test set at 1000V

When installed properly it will last for years, the problem comes when other sparks mess around with it once in place.

yep one end at a time when i was a lad we sat in lock up making ends off on all the coils of pyro /micc then when cable was needed one end was already made off for the spark also good practice for us,big trouble if any burs where left in pot! LOL

 

[trev]

"its outdated and you should be using fp200"......surely this lecturer should see that you use the most appropriate cable/s for the installation/environment...including pyro......so what he was saying was a load of crap.......

The same guy would probably say in every circumstance that you WILL use 2.5 for socket outlets.
Knob

 

[GLENNSPARK]

The same guy would probably say in every circumstance that you WILL use 2.5 for socket outlets.
Knob

the thing is here n all Trev...is lecturers and those who take up jobs passing knowledge on shouldn`t be negating to teach the pro`s n cons of different cable/s and systems on the basis that `its old hat`...or some other nonsense like that....i mean...how are folk supposed to learn with dismissive attitudes like this.....

 

[GLENNSPARK]

The same guy would probably say in every circumstance that you WILL use 2.5 for socket outlets.
Knob

and further to this n all trev....is the fact that to get over the issues of derating for insulation....you may find yourself using 4.0mm......a lot of newbuilds have insulation under floors and in ceiling voids now.....

 

[UNG]

When installed properly it will last for years, the problem comes when other sparks mess around with it once in place.

You would have to enlighten me as to what the problem is "when other sparks mess around with it once in place" I have altered many Pyro installations that were installed many years before with no problems whatsoever. In fact the only problem if it is a problem is more skill and understanding of the cable is needed to modify an installation that has been in place for a number of years

 

[ackbarthestar]

I would agree, there is not enough training and consequently not enough experience when dealing with this cable system. So somebody without the necessary experience is likely to degrade the cable through poor connections.

 

[Snapester]

Hi guys, went back to this job today to have a look at the issue, and apparently it was sparking at the cooker switch but no signs of blackening etc so dubious about that! Although the customer had ripped down a wall cabinet exposing the original outlet which had been chock blocked and the fitting looked a little rusty, it was spidered off from here!!
I Tested the Continuity of CPC - Line was good 0.09 and Line-Line 0.06, the insulation test was however at 32.3Mohms so not great but for the age i would say its good.
After poking about the 4mm PYRO is supplying 2x Socket Outlets, Cooker Hood, 7Kw Hob & Cooker on 13amp plug and also washing machine!! Possible overload as this is on a 32a breaker although it had not tripped!
Now looking in my greenbook of answers it shows me that 4mm PYRO Bare & Not exposed to touch nor i contact with combustable material but it only shows clipped direct or on tray? This is in a Concrete wall?? What is the CCC of it would it be around 40a? as the load i would estimate is around 45amps if it was fully loaded!!

Cheers

 

[ackbarthestar]

I think MI cable is rated at 55A clipped direct and 60A on tray, heavy duty and 51A and 54A for light duty (App4. table 4G2A)

Its more likely to be those woosy washing machines causing some form of capacitive discharge !

 

[Snapester]

Yeah i see it as 51A clipped or 54A on a tray? No word of in a wall? I have told the customer that it would be better to install a small circuit to take the kitchen sockets and washing machine and leave the MI for the cooker and hob?
Although i don't believe the circuit to be overloaded if the 32A MCB has not even tripped out and its unlikely the MI would have become overloaded, i think more bad connections in the awful joint hidden behind the wall unit?

 

[rich.250]

If its not a thermal insulated wall I would say clipped method.

 

[Snapester]

Would you guys class that cable as being overloaded?