I recently came across Pyro that had been sitting cut off in a damp basement. The last time made off Pyro was 3 years ago.
I have various cut offs and pots & glands with the intention of occasionally keeping in practice.
I had read all sorts of things from them in the past and seen various videos from them that look like they were made in the 70s.
Two things I remember from them that they said are myths:
(1) That moisture continues to get absorbed all the way through the cable. It only goes about 300mm and,
(2) Screwing on the pot until the inner shoulders are level. It should be through 3mm.
I have opened a few pots that have been outside for years. Even with a shroud moisture still gets in. The putty is sometimes green from the copper oxide.
They said that it still gets though the thread on the pot. I tried this out and it's true. I screwed a pot on to cable and put the lower part in water for 8 hours. A bead of water got though to the inside. That's why you should go through 3mm. It allows the putty to not just seal the thin edge, a dubious seal, but 3mm around the side as well.
Anyway, back to the first myth.
This Pyro is in a damp basement, and I mean damp. It gets flooded when raining and has a sump pump.
It must have been sitting cut off for over ten years.
An ideal opportunity to see if what they said holds up. I had to cut it away anyway so I decided to cut it 1 metre back, strip the cut bit to access the conductors and do an IR on it. As expected IR was about 0.05 Meg. I then started stripping the end that was exposed. As I did the IR started going up until I got to >999 at about 300mm.
So there you go. It's true.
However:
There are two strange things that have happened. Pyro is supposed to be "everlasting", and maybe it will last a lifetime in most cases but I tried this on another 5 metre piece of Pyro, that was inside a warm environment, that was around 25 years old.
I cut from both ends, making sure that the conductors were away from the sheath after the cut, and although the IR went down a bit, it still stayed at around 25 Meg. Just in case there was damage that was so small I could not see it I cut it in half and done the same to both halves. I then tried this with some more old Pyro from a different building on the same site and another site and as soon as I cut off the ends the IR went right up to >999.
I have not done this experiment before (nor do I intend to do it again) so I don't know how many lengths of Pyro behave like this but it seems strange that with the fact that moisture does not get absorbed more that 300mm it has managed to infiltrate this particular Pyro all the way along the length to give it an IR of 25 instead of >999.
Anyway, you may be wondering about the "Super Magic" bit in the title.
There is one bit of Pyro that behaved in a strange way. Before I came across the one sitting in the damp basement I had taken a small length of Pyro home to see how deep the moisture penetration would go after a day/week/month.
Now I had heard that the magnesium oxide had been improved to resist moisture (although I don't know if that's really true) but this bit surprised me.
I cut it off one end, stripped and sealed to have the conductors to test from, then cut 400mm the other end.
Tested >999
Left 1 hour >999
12 hours >999
1 day >999
Strange. Put the end on the spout of a boiling kettle.
Tested 0.50
1/2 hour >999 .... WHAT!
Dipped it in water for ten mins.
Tested 0.00
1 min same.
1/2 hour about 400
1 hour >999.
DA DAA! SUPER MAGIC PYRO.
And yes, I did check the batteries in the tester. MFT1710.
Any thoughts on these 2 strange anomalies?
I have various cut offs and pots & glands with the intention of occasionally keeping in practice.
I had read all sorts of things from them in the past and seen various videos from them that look like they were made in the 70s.
Two things I remember from them that they said are myths:
(1) That moisture continues to get absorbed all the way through the cable. It only goes about 300mm and,
(2) Screwing on the pot until the inner shoulders are level. It should be through 3mm.
I have opened a few pots that have been outside for years. Even with a shroud moisture still gets in. The putty is sometimes green from the copper oxide.
They said that it still gets though the thread on the pot. I tried this out and it's true. I screwed a pot on to cable and put the lower part in water for 8 hours. A bead of water got though to the inside. That's why you should go through 3mm. It allows the putty to not just seal the thin edge, a dubious seal, but 3mm around the side as well.
Anyway, back to the first myth.
This Pyro is in a damp basement, and I mean damp. It gets flooded when raining and has a sump pump.
It must have been sitting cut off for over ten years.
An ideal opportunity to see if what they said holds up. I had to cut it away anyway so I decided to cut it 1 metre back, strip the cut bit to access the conductors and do an IR on it. As expected IR was about 0.05 Meg. I then started stripping the end that was exposed. As I did the IR started going up until I got to >999 at about 300mm.
So there you go. It's true.
However:
There are two strange things that have happened. Pyro is supposed to be "everlasting", and maybe it will last a lifetime in most cases but I tried this on another 5 metre piece of Pyro, that was inside a warm environment, that was around 25 years old.
I cut from both ends, making sure that the conductors were away from the sheath after the cut, and although the IR went down a bit, it still stayed at around 25 Meg. Just in case there was damage that was so small I could not see it I cut it in half and done the same to both halves. I then tried this with some more old Pyro from a different building on the same site and another site and as soon as I cut off the ends the IR went right up to >999.
I have not done this experiment before (nor do I intend to do it again) so I don't know how many lengths of Pyro behave like this but it seems strange that with the fact that moisture does not get absorbed more that 300mm it has managed to infiltrate this particular Pyro all the way along the length to give it an IR of 25 instead of >999.
Anyway, you may be wondering about the "Super Magic" bit in the title.
There is one bit of Pyro that behaved in a strange way. Before I came across the one sitting in the damp basement I had taken a small length of Pyro home to see how deep the moisture penetration would go after a day/week/month.
Now I had heard that the magnesium oxide had been improved to resist moisture (although I don't know if that's really true) but this bit surprised me.
I cut it off one end, stripped and sealed to have the conductors to test from, then cut 400mm the other end.
Tested >999
Left 1 hour >999
12 hours >999
1 day >999
Strange. Put the end on the spout of a boiling kettle.
Tested 0.50
1/2 hour >999 .... WHAT!
Dipped it in water for ten mins.
Tested 0.00
1 min same.
1/2 hour about 400
1 hour >999.
DA DAA! SUPER MAGIC PYRO.
And yes, I did check the batteries in the tester. MFT1710.
Any thoughts on these 2 strange anomalies?