enclosure for joining big swa

[johnmf]

hi guys, not a DIY question but ive seen some previous posts on here from sparks who may be able to help me out so thought id ask......

i have picked up a job which involves joining big swa cable (ive worked with 150mm before but have been doing domestic for last few years)

situation is a 240mm 4 core swa coming up out of a duct at floor level and sitting vertically against a wall, cable only comes out of floor by 700mm. i need to join this to another piece of big swa that will go on to feed a busbar.(this is all inside a building by the way)

the new cable can be 240mm or i can go down to 185mm (will be fused correctly obviously and loading assessed with plenty to spare)

i have two options as i see it,

1, use a resin joint kit or a heatshrink joint kit (additional protection will be assessed and provided). problem i see with resin kit is it could be fun to fill seen as the submarine will be vertical!

or i can use a suitably rated enclosure and either lug the cables onto terminals or thru crimp them (an enclosure is my preffered method). can anybody suggest a particullar make of enclosure that would be suitable????

also has anybody used the shear bolt joints? if so are they any good and can they be used to join 240 to 185 cables?

opinions please.

regards

 

[Lectrician]

Excavate the concrete and resin joint, or use a suitably rated busbar chamber as a joint.

 

[johnmf]

you think this will be the way to go lectrician?

i want to make sure the earth continuity of the swa is good and the resin joints ive used previously for big stuff has been poor to be honest.

can you get resin kits that fill from the top? this could be a problem as the cable will be vertical and the resin kits ive seen fill from the middle.

 

[ricicle]

Can you not make the resin joint off first with the cables horizontal.Let it set and then put into it's vertical position (cleating etc)?

 

[johnmf]

thanks for the interest so far,

unfortunetly its not possible to do the joint first as the 240mm swa cable only comes out of the ground 700mm so obviously cant bend it to do the joint horizontally!

 

[gcresser]

also has anybody used the shear bolt joints?

Yes, to do exactly what you want to do. One thing to remember though. Lay the new cable the right way round - so that cores line up. Put the other way and you'll have to bend the cores - not very easy with 240mm. Also you may need some core twisters to get them to lie correctly in the connector.

You could use crimps, but you'll have to fork out £00s for a crimper. Buy a bigger resin joint than suggested if using shear bolt connectors as these are bulky and will take up a lot of valuable space in the joint.

I'd cut back underground. The one i did took 28 litres of resin and was about 1.2m long!

Is one of the cores earth or is there a sperate earth?

see http://www.cableservices.co.uk/ for materials. Although I got my joint from the DNO.

 

[ricicle]

Steel adaptable box with insulated threaded studs fitted, then use lugs to bolt on.

What is your budget? How about an isolator?

Are you also known as Jim23?

 

[johnmf]

the earthing is currently the swa of the cable..... ill be looking into that to see if it is adequate for earthing as i suspect it doesnt.

the fact that the armour is the earth is why im put off the resin joint as i hate the continuity straps. i prefer to gland into a decent enclosure.

im contemplating using the shear bolt joints inside an enclosure and heat shrinking the bolts. the shear bolts i believe allow me to downsize the cables and join 240 to 185mm.

 

[johnmf]

hi ricicle,

yes, ive posted a similar thread on the IET website.

the budget is not really an issue. Thought about a switch fuse isolator but i consider its going to be easier to crimp two cables together than bolt them onto some bottom terminals in a switchfuse (du to the fact that there is hardly any cable coming out from the duct).

regards

 

[gcresser]

Use insulating patch, much stronger and eliminates the risk of hot working. (risk assessment)

Can get the details of what it's proper name tomorrow if you want. It's the stuff that only sticks to itself when the backing is removed. So you simply wrap it around the connector.

 

[briwire]

I'd go for an isolator with spreader boxes or even a busbar chamber box.

 

[Lectrician]

you think this will be the way to go lectrician?

i want to make sure the earth continuity of the swa is good and the resin joints ive used previously for big stuff has been poor to be honest.

can you get resin kits that fill from the top? this could be a problem as the cable will be vertical and the resin kits ive seen fill from the middle.

I said excavate You would need to excavate to allow cable to lie flat and allow room for joint. Joints have to be flat. A resin joint is also designed to be buried - not sat on a wall!

I would still go the busbar route. An adaptaple galv box is not up to this job.

 

[tim west]

Use insulating patch, much stronger and eliminates the risk of hot working. (risk assessment)

Can get the details of what it's proper name tomorrow if you want. It's the stuff that only sticks to itself when the backing is removed. So you simply wrap it around the connector.

Self amalgamating tape/patch?

 

[gcresser]

Yes, it is Self amalgamating patch, just trying to get the proper name (I'm sure it's not what you imagine it to be called!!!)

 

[ricicle]

An adaptaple galv box is not up to this job.

Sorry, adaptable box was not what I meant.You can get some fairly hefty steel enclosures though...