Self Amalgamating Tape

[Taylortwocities]

As I started work more than 10 years before you I guess I have more electrical experience than you.

10 years? How could you know what year I left school and started work? Have you been stalking me?

 

[winston1]

since I started work in 1972

Yeah, sorry wrong person.

 

[SUNRAY]

https://en.wikipedia.org/wiki/Self-amalgamating_tape

it is heat-, sunlight-, and weather-resistant.

You trust Wikipedia, which anyone can update, more than people who have over 50 years experience of using the stuff? Wow!
Can I suggest you go to the internet and research how rubber perishes.

Wrapping a joint in self amalgamating tape is not a bodge. It self amalgamates and is as good as the original outside sleeving.

Yes, I know what SA tape is, I have been using it for over 50 years.
ANY joint is a breach of the integrity of the original cable so it's a question of managing the situation. SA tape does NOT amalgamate with PVC (in fact with hardly anything). What you end up with is a rubber sleeve stretched around the object, just like using a suitably stretched Hellermann sleeve or rubber pipe, and if there is any impurity (especially grit or grease) trapped at/in the junction it can very rapidly suffer

Perhaps BT were using poor quality cheap stuff.

Categorically not the case.

By who?

By some companies and indivuals who have an exceptionally high quality approach to their professionalism and don't want their systems to fail.


SA is not 'banned' by all commercial institutions (and I don't think it should be). These days I'm finding professional joints often contain 3 or 4 layers of tape. On mobile phone masts (where moisture ingress is far more critical to continued operation than an electrical cable) I often find 2 methods: A first layer of yellow or red PVC (I don't know if the colour is relevant)-sticky side out, SA, and finally black PVC. OR SA, PVC, Denso and finally black PVC. Each layer extends past the previous by about an inch. I'm sure these people wouldn't waste the time and money if they don't need to

.

 

[ericmark]

I have used tape like @SUNRAY says, the insulation tape stops unwanted electrical contacts and the self amalgamating tape stops water ingress. Yes a proper cable joint is better, be it epoxy resin shrink sleeve or potted, but the self amalgamating tape is faster and you can get into it again latter if required, although not easy.

Also used Denso tape and it does not stand the test of time, when we ran out of cable joints on Falklands, to keep things running we used Denso tape mapping all joints so we could return and do the job proper once the supplies arrived, one must have been missed, 350 kVA out of generator shed, but adding the power to each unit supplied should only need 250 kVA, seemed likely a bad joint, but where? Lucky that night it snowed, next morning there was a circle of melted snow, and yes found Denso tape joint, it had been there for 3 years plus so I suppose not bad, but think Denso tape is for plumbers not electricians.

 

[SUNRAY]

I have used tape like @SUNRAY says, the insulation tape stops unwanted electrical contacts and the self amalgamating tape stops water ingress. Yes a proper cable joint is better, be it epoxy resin shrink sleeve or potted, but the self amalgamating tape is faster and you can get into it again latter if required, although not easy.

Also used Denso tape and it does not stand the test of time, when we ran out of cable joints on Falklands, to keep things running we used Denso tape mapping all joints so we could return and do the job proper once the supplies arrived, one must have been missed, 350 kVA out of generator shed, but adding the power to each unit supplied should only need 250 kVA, seemed likely a bad joint, but where? Lucky that night it snowed, next morning there was a circle of melted snow, and yes found Denso tape joint, it had been there for 3 years plus so I suppose not bad, but think Denso tape is for plumbers not electricians.

With all things there is an element of doing the job properly. About 15 years ago we removed a 100ft 2ndWW oak lattice mast

the majority of the remaining feeders plugs were wrapped in Denso, including the original armoured coaxes, and only one of about 40 showed any sign of failure. All of the heliax's were carefully removed for re-use elsewhere.
The Denso joints on that mast were several layers of Denso then 2 layers of insulating tape (not PVC) finished with a copper wire tie at each end of the joint.
Elsewhere I've encountered Denso without the additional layer or tie with very mixed results.

 

[winston1]

I'm sure these people wouldn't waste the time and money if they don't need to.

You have more faith in big business and other peoples money than I do then.

 

[crystal ball]

As I said I have never had problems with it over many years on satellite installations.

Perhaps BT were using poor quality cheap stuff. These large organisations tend to go on price rather than quality these days. Usually choose the second cheapest.

You are familiar with blue chip companies procurement systems are you?

 

[Taylortwocities]

He's an expert in just about everything.

 

[SUNRAY]

You are familiar with blue chip companies procurement systems are you?

Apppppaaaarrrennnnntly not!!!!!!

 

[ericmark]

Think your mast above ground is a little more forgiving than buried under ground. How many worms have you found up the masts?

 

[SUNRAY]

Think your mast above ground is a little more forgiving than buried under ground. How many worms have you found up the masts?

Not as many as birds that peck and eat, various bugs that like to build their houses in little gaps and extremes of hot and cold, wet, dry and windy etc. Apart from the act of digging I'd much rather be working on and/or repairing the minor works required underground. Yes I do both and I can state from experience that a grotty PVC tape joint will generally last a lot longer buried U/G than tens of metres up in the air. EDIT: There is also a vibration issue to contend with aloft.

For those who have not climbed a structure of this ilk (often on top of a hill of some sort) getting above ground level turns hostile very quickly. Even on a hot summer day I would expect to wrap up very warm as the temtarature drops rapidly.



But as is often the case this is getting a long way from the topic of self amalgamating tape.

 

[SUNRAY]

I made a big mistake with this job:

I unexpectedly had to replace weather resistant cable ties which had failed in about 3 years and refix a feeder to the mast. I didn't have overalls and coat and I managed to book a 1 hour slot of the mobile cell switched off. Ss it was a hot day (ground crew in shirt sleeves) I climbed wearing jeans and T shirt & jumper. Big mistake, I was frozen and shivering by the time I'd finished.

 

[SUNRAY]

A very merry Christmas to everyone and a happy, healthy and prosperous new year.

 

[bernardgreen]

By who?

Among others, engineers responsible for installing and maintaining radio communications equipment for the emergency services.

 

[SUNRAY]

Today I helped clear redundant debris from the above pictured mobile phone mast.
This is how self amalganising tape is used by properly trained, professional aerial riggers:

I know it doesnt show very well but that's a single layer of PVC tape, sticky side out then SA [or could be SV] tape to about 3mm thick, 2 layers of black PVC tape and lastly 2 layers of grey PVC tape.

These coax ofcuts were the last remnants of the Orange system installed there in the early 1990s so around 27 years old, the cable and plugs look like new inside there.