mineral insulated cable repair

[UNG]

Surely Ung, SWA is a mechanically stronger protection than the thin copper sheath on a pyro ?

The size and type i.e. heavy or light has never been mentioned even so Pyro in any size will take some stick before it gives up try flattening a piece with a hammer and see how much it takes before the insulation resistance is to low to be viable to use it

By comparison SWA is PVC that in cold conditions is likely to shatter if you hit with a hammer and in warmer conditions it wouldn't fare much better

As Trev says you would still need all the same protection measures for both cables if you are installing them correctly

 

[Guest55]

If an MICC has been damaged then replacing it with SWA does not solve the mechanical protection problem without other mechanical protection measures being deployed

repairing a damaged swa is a 15min fix with basic tools and basic skills
repairing a damaged pyro is not.
;-)

Edit;
and for that reason alone , swa is more suitable than pyro for underground power.
either customer replaces cable or walk - you could spend hours faffing with it just to get it upto a meagre 2 Meg.
and as someone who has worked on jointing teams i know which i'd prefer to fix :-D

 

[clematis432]

The size and type i.e. heavy or light has never been mentioned even so Pyro in any size will take some stick before it gives up try flattening a piece with a hammer and see how much it takes before the insulation resistance is to low to be viable to use it

By comparison SWA is PVC that in cold conditions is likely to shatter if you hit with a hammer and in warmer conditions it wouldn't fare much better

As Trev says you would still need all the same protection measures for both cables if you are installing them correctly

The original thread was a cable being cut while digging in the garden (spade probably) Not " being hit with a hammer" I think the mechanical strength of SWA is better than pyro regarding accidental gardening damage. Obviously the correct installation methods must be followed.

 

[Carnegstar]

You can fix this damaged cable.
Just use the blowtorch as mentioned, also the pots with the earth flyers built in will make it easier.

I succesfully repaired a 2core pyro with glands i found in my van that were too small, i drilled them out to nearly the correct size and soldered them on using the blowtorch again. you just have to enjoy a challenge and take some time.

 

[thekingiam]

everyone has said everything about pyro so i have nothing to add!
oh yeah check polarity by linking each core to outer metalic sheath each end.( obvious i know, but like i said i have nothing to add)

 

[UNG]

repairing a damaged swa is a 15min fix with basic tools and basic skills
repairing a damaged pyro is not.
;-)

Edit;
and for that reason alone , swa is more suitable than pyro for underground power.
either customer replaces cable or walk - you could spend hours faffing with it just to get it upto a meagre 2 Meg.
and as someone who has worked on jointing teams i know which i'd prefer to fix :-D

You don't enjoy a challenge then, spent many hours working on Pyro the Rolls Royce of cables in my opinion no other single cable can do what Pyro does on it's own it's only downfall is the deskilling of this industry where the operatives involved want the easy life of installing FP --- or it's derivatives and in most installations I've come across can't even get that right especially for fire alarm installations

The original thread was a cable being cut while digging in the garden (spade probably) Not " being hit with a hammer" I think the mechanical strength of SWA is better than pyro regarding accidental gardening damage. Obviously the correct installation methods must be followed.

So either cable installed correctly = no problem as said previously there is no mention of "L" or "H" Pyro the original installation from the brief description given would have been better suited to heavy duty Pyro but without input from the OP we will never know

You can fix this damaged cable.
Just use the blowtorch as mentioned, also the pots with the earth flyers built in will make it easier.

I succesfully repaired a 2core pyro with glands i found in my van that were too small, i drilled them out to nearly the correct size and soldered them on using the blowtorch again. you just have to enjoy a challenge and take some time.

I'm with you, I like this someone with a can do attitude fix it walk away and forget the SWA

 

[clematis432]

Think Ung,s got shares in a Pyro company or is just merely infatuated with it !
Both cables have merits but my opinion regarding original post (underground installation of cable) SWA is better.
I worked for many years(till redundancy) in a very large GSK site/factory and there was many hundred of miles of underground cabling the VAST majority of it SWA(99%) Think most of UK,s underground cabling will be the same.
I,m sure cost of Pyro is another factor of why it,s not used as much as SWA underground.
Also Ung, your rather harsh on electricians regarding their "can,t even get that right" when it comes to pyro install.
I,m sure most of them have been asked to do it without much previous exposure or training. After a bit of practise, you don,t need to be such a clever clogs to put a Pyro gland on.

 

[Guest55]

You don't enjoy a challenge then, LOL , i prefer to take a realistic view on tackling jobs these days , and my current work is fairly demanding.
spent many hours working on Pyro the Rolls Royce of cables in my opinion no other single cable can do what Pyro does Yes its durable stuff , but it was designed as a fireproof #cable and its weaknesses become apparant when used underground.
on it's own it's only downfall is the deskilling of this industry where the operatives involved want the easy life of installing FP --- or it's derivatives and in most installations I've come
across can't even get that right especially for fire alarm installations
cant really comment on that point.

.............

 

[Engineer54]

Don't really know what all the fuss is about, this is a relatively easy fix for anyone that knows how to work MICC cable. Just use the made for purpose screwed tube, two ends to make of with pot's and glands and crimp core connections. I take it that the cable in question is of the PVC covered variety, so that needs to be stripped back to allow the glands to slip on the cable etc.

If your worried at all about condensation forming within the tube underground, it can be filled with a suitable material prior to fitting the second gland to the tube. Then to finish off, ...an overall internal glued heat shrink tube between each of the two cable ends PVC over sheath encapsulating the the termination. A few necessary tests performed ...Job done!!! For the actual termination, round an hours work!!!

 

[imago]

For the actual termination, round an hours work!!!

Agreed, and to dry it out enough to get a decent IR reading? Given that the ground is currently soaked, and that the cable ends have been open out doors for some time as well as being in the groud when it was cut into, you will have over a metre in both directions to dry out at the minimum. So if a days labour is cheaper than a length of SWA then fine, but bear in mind you'll have to dig it all up anyway. Firstly to dry it out, and secondly as you've worked on it you will now need to make sure it's at a suitable depth and marked.

MIMS/MICS is brilliant stuff, and I love working with it, especially on jobs where you have time to make a feature of it. In this instance however, it doesn't make economic sense for either the customer or the contractor to faff about with it.

 

[ttelec]

many thanks for all your replies persuaded customer to have it replaced with swa in the end and its now completed thank god

 

[UNG]

Think Ung,s got shares in a Pyro company or is just merely infatuated with it !

Not enough Pyro used these days to make it worth while having shares and yes I do like Pyro

Both cables have merits but my opinion regarding original post (underground installation of cable) SWA is better.
I worked for many years(till redundancy) in a very large GSK site/factory and there was many hundred of miles of underground cabling the VAST majority of it SWA(99%) Think most of UK,s underground cabling will be the same.
I,m sure cost of Pyro is another factor of why it,s not used as much as SWA underground.

I agree SWA is a better underground cable but the OP in this thread was about a damaged underground Pyro that could easily be repaired

Also Ung, your rather harsh on electricians regarding their "can,t even get that right" when it comes to pyro install.
I,m sure most of them have been asked to do it without much previous exposure or training. After a bit of practise, you don,t need to be such a clever clogs to put a Pyro gland on.

The "can't even get that right" was in reference to the the installation of FP --- or it's derivatives in fire alarm installations if installing part of a safety installation incorrectly is harsh then I don't understand your priorities
I agree anybody can put a gland and pot on a Pyro the skill is doing it consistently and quickly a friend of my mum's worked in BICC where they made up pre terminated Pyro kits they termed the Pyro on piece work at something like 3 minutes per end to make their money any cables that failed test didn't get paid. The art of Pyro is clipping and working it and getting it neat

Originally Posted by UNG
You don't enjoy a challenge then, LOL , i prefer to take a realistic view on tackling jobs these days , and my current work is fairly demanding.
spent many hours working on Pyro the Rolls Royce of cables in my opinion no other single cable can do what Pyro does Yes its durable stuff , but it was designed as a fireproof #cable and its weaknesses become apparant when used underground.
on it's own it's only downfall is the deskilling of this industry where the operatives involved want the easy life of installing FP --- or it's derivatives and in most installations I've come
across can't even get that right especially for fire alarm installations
cant really comment on that point.

You mean you have never taken a realistic view in the past, if you create more work than necessary I can see how it is demanding
I agree it was designed as a fireproof cable it's only weakness underground IMO is where light duty has been used and not heavy duty

Agreed, and to dry it out enough to get a decent IR reading? Given that the ground is currently soaked, and that the cable ends have been open out doors for some time as well as being in the groud when it was cut into, you will have over a metre in both directions to dry out at the minimum. So if a days labour is cheaper than a length of SWA then fine, but bear in mind you'll have to dig it all up anyway. Firstly to dry it out, and secondly as you've worked on it you will now need to make sure it's at a suitable depth and marked.

MIMS/MICS is brilliant stuff, and I love working with it, especially on jobs where you have time to make a feature of it. In this instance however, it doesn't make economic sense for either the customer or the contractor to faff about with it.

I have never seen Pyro draw up moisture for over a metre even with the ends left in a bucket of water for couple of months and depending on the age of the Pyro it may have the newer siliconised insulation material which doesn't draw up moisture as much. Wouldn't have thought you would be looking at a day to complete this even at a worse possible

 

[malcolmsanford]

I can only comment on the MICC I have worked on, but I have had rolls of MICC that have sat in the stores for yonks, and mostly the outside stores as it wasn't what you would call "fast moving" and I have never had to cut a metre off it for moisture ingress, for us 6" was the normal.

Now unless like everything else in our industry in regards to material and quality, the modern MICC is rubbish and you do indeed need to crop of metres of it find a good dry end.

Also what made me laugh is drying it out, using blow torches. I can remeber to this day a sparks soaking some MICC in water overnight, and when he made the end of next day it was barely above full scale deflection (that how long ago it was, bet E54 and tony remember those meters) and he disconnected the earth and powered up .................after 20 mins we tested again and perfect .................just to prove to me that drying out MICC was a piece of ................

 

[imago]

I can only comment on the MICC I have worked on,

Likewise, I've had rolls from the supplier where the first couple of inches was causing problems getting a decent IR. Cut it back and all was fine. The cable the OP is referring to has been in wet earth for some time, so it will have been exposed to moisture, salts and minerals.

Sitting here typing away I cannot say for certain it's going to have drawn moisture for a specified distance, or exactly what type of cable it is, and neither can anyone else. It may be fine, it may be screwed for some distance, there maybe more than one point of impact from the spade.

 

[UNG]

I can only comment on the MICC I have worked on, but I have had rolls of MICC that have sat in the stores for yonks, and mostly the outside stores as it wasn't what you would call "fast moving" and I have never had to cut a metre off it for moisture ingress, for us 6" was the normal.

Same for me, I have a vague recollection that the moisture does not travel more than 12 inches down the cable however long it's exposed to damp or water

Now unless like everything else in our industry in regards to material and quality, the modern MICC is rubbish and you do indeed need to crop of metres of it find a good dry end.

If anything the newer cables should be less prone to damp as they started moving over to a moisture resistant insulation round about 20 - 25 years ago

Also what made me laugh is drying it out, using blow torches. I can remeber to this day a sparks soaking some MICC in water overnight, and when he made the end of next day it was barely above full scale deflection (that how long ago it was, bet E54 and tony remember those meters) and he disconnected the earth and powered up .................after 20 mins we tested again and perfect .................just to prove to me that drying out MICC was a piece of ................

I have used a blowtorch or heat gun to dry out Pyro in a similar repair situation as the OP, in normal use most of the Pyro I have made off had to have long tails so the damp section was stripped away in the termination process. Then again there was a time when you could term a Pyro with a blowtorch when they introduced the heatshrink seals in 1980 they were never a big hit and were discontinued about 10 years later