Pyro Meter Tails!

[Piratepete]

:willy_nilly: Domestic client called me to quote for some sockets and a CU change. Stunned to see the meter connected to the existing fuse box by 2 core pyro using the bare sheath as the earth conductor. Was this common practice in the 70s and did it comply back then or even now?

The supply is 60 Amp, the Fusebox is some 4 metres from the meter. The termination of the cable is enclosed at the fusebox end but not in the cutout/meter box where the two single insulated tails connect directly into the meter. The cable diameter (bare) is 13.39 mm. Can't seem to find this in my tables to check the rating.

Is there anyway I can reuse the pyro, as replacing it will be a nightmare! Because of the distance, I'm thinking of installing a 60A switch fuse in the meter box and try to get the cut-out upgraded to 80 Amps (minor point of compliance).

Cheers
Pete

 

[davesparks]

In some parts of London it was once a requirement to use pyro for the tails, can't remember which boroughs but I might be able to find out. I think Chelsea may be one of them.

If it tests out ok then of course you can reuse the pyro, it's a damn sight better cable than any plastic insulated carp. You might wish to apply some heatshrink to the tails as they connect in to the meter though, but if you are fitting a sw fuse then just gland it in to that as normal.

 

[trev]

:willy_nilly: Domestic client called me to quote for some sockets and a CU change. Stunned to see the meter connected to the existing fuse box by 2 core pyro using the bare sheath as the earth conductor. Was this common practice in the 70s and did it comply back then or even now?

The supply is 60 Amp, the Fusebox is some 4 metres from the meter. The termination of the cable is enclosed at the fusebox end but not in the cutout/meter box where the two single insulated tails connect directly into the meter. The cable diameter (bare) is 13.39 mm. Can't seem to find this in my tables to check the rating.

Is there anyway I can reuse the pyro, as replacing it will be a nightmare! Because of the distance, I'm thinking of installing a 60A switch fuse in the meter box and try to get the cut-out upgraded to 80 Amps (minor point of compliance).

Cheers
Pete

The pyro will outlive you, me and my grandson mate and he's only 3. New gland on the switch fuse and you're good to go.
You're ok with glanding pyro aren't you?

 

[Piratepete]

The pyro will outlive you, me and my grandson mate and he's only 3. New gland on the switch fuse and you're good to go.
You're ok with glanding pyro aren't you?

Thanks. Your reply not unexpected. No, never done anything with Pyro!

 

[trev]

I love the stuff mate, it can be a bit unforgiving though so if you have any doubts about how to handle it you might want to ask one of your pals who has used it before.
If it goes wrong it can be a ballache.

 

[shanky887614]

I love the stuff mate, it can be a bit unforgiving though so if you have any doubts about how to handle it you might want to ask one of your pals who has used it before.
If it goes wrong it can be a ballache.

trev is right, make sure to at least have a potting tool, stripper is optional but the crimper is very highly recommended.

why not try on some off cuts before taking on this job, no point making yourself look a fool in front of client

 

[trev]

It's an expensive learning curve though Shanky unless he can pick up some scrap ends from somewhere. It'll be even more expensive if he gets it wrong though
You're right though, potting tool is a 100% must have.

 

[trev]

If you google MICC termination video you'll get some idea of what's involved mate.

 

[shanky887614]

look on ebay there are some deals to be had

people sell it for £3+ m

but then there are people like this that are selling 130 for £30

remember there are multiple different sized potting tools f = 16mm
20mm,25 and i think 30 but im not sure about any others

 

[jaypp]

trev is right, make sure to at least have a potting tool, stripper is optional but the crimper is very highly recommended.

why not try on some off cuts before taking on this job, no point making yourself look a fool in front of client

Haven't you got any left you can offer him?

 

[davesparks]

The OP has said the cable is 2 core overall diameter is 13.39mm, that suggests that it is an imperial cable as it is an exact match for 2 core 0.0145".
To confirm this the markings on the pot and gland will be either 527 or 594.
The nearest match metric equivalent parts are:
Gland - RGM 3H10 25
Pot - RPS 3H10 25 (requires soldering onto cable sheath)
Seal - RPS 2H10 25

Current rating for bare (14th edition regs) 70Amps, volt drop 4.5 mV/A/m

This is taken from the pyrotenax imperial to metric conversion chart for MICC

If it is the imperial cable then it will need more experience than a couple of practice ends before tackling the job. It'll more than likely need a bit of annealing and lots of fettling to work it without it snapping/cracking.

The nearest metric 2 core MI to that diameter is:
2H6 - 12.6mm
2H10 - 14.4mm

 

[davesparks]

remember there are multiple different sized potting tools f = 16mm
20mm,25 and i think 30 but im not sure about any others

Pots are referenced to the size of the thread on the gland, so follow the same standard sizes of everything
Ie 20mm, 25mm, 32mm and 40mm.

20mm and 25mm crimpers are available as the hand operated type whilst the 32mm and 40mm are only available as the 3 bolt & plates type.

 

[davesparks]

Ye gawds I'm a sad barsteward!

 

[trev]

Ye gawds I'm a knowledgeable barsteward!

Fixed that for you Dave.

 

[shanky887614]

Pots are referenced to the size of the thread on the gland, so follow the same standardization sizes of everything
Ie 20mm, 25mm, 32mm and 40mm.

20mm and 25mm crimpers are available as the hand operated type whilst the 32mm and 40mm are only available as the 3 bolt & plates type.

actually dave ive got a smaller than 20mm crimpers on my desk


f type is 16mm.

a lot of motors we get have 16,20,25mm threads etc so all standard size but everyone starts at 20mm for some reason

 

[shanky887614]

and we are all sad barstewards chatting on here when we should all be sleeping, im up in 6 hours hopefully i dont wake up at 2am again like yesterday

 

[davesparks]

actually dave ive got a smaller than 20mm crimpers on my desk

I never said you didn't did I? I've got a set of 16mm crimpers lurking somewhere along with some 5/8" and 3/4"

What I listed is only those that are currently in production and relevant to the topic.

16mm is still listed as a standard size of conduit, but good luck getting hold of it! It's a relic from the days of imperial stuff, 5/8,3/4,1,1 1/2, 2 became 16,20,25,32,40(38),50(52)

I've got 16mm conduit taps and dies, taps were used for fitting 16mm stuffing glands into some scaff tube, the dies are unused.

 

[shanky887614]

i thought they still made 16mm pots, guess not then

 

[davesparks]

i thought they still made 16mm pots, guess not then

Expanded on that post a bit now

 

[appspark]

If you google MICC termination video you'll get some idea of what's involved mate.

In college we got shown a video called, wait for it, "The Terminator" straight from the 1970's prysmian factory.
We still use pyro on alot of our jobs for fire alarms, nothing quite like ordering 500 glands to cheer you up.