25mm armoured

[wellshocked]

was just wondering if this was the correct size, any help would be appreciative

a 25 mm armoured with a run of about 25 metres , ambient temputure 25degrees, clipped on its own direct to a wall.
it is feeding a supply of a 100 amp switch

someone told me it should be downgraded to a 80 amp , but i cant see whats wrong with it being as it is.

also , i been told that you have to earth cable tray, i always thought that if it was rcbo protected you wouldnt have to do it , am i wrong?


cheers

 

[timbobelfast]

25mm ok as 100 amps and just good practice to earth containment.

 

[wellshocked]

cheers for that , it was just a few problems my mate is having on some job he was working on. some one has come on site and slated everything coz he didnt get the job.(he basically always gets the work but didnt get this job) even moaned at the spacing of the cleats.lol

 

[Amp David]

was just wondering if this was the correct size, any help would be appreciative

a 25 mm armoured with a run of about 25 metres , ambient temputure 25degrees, clipped on its own direct to a wall.
it is feeding a supply of a 100 amp switch

someone told me it should be downgraded to a 80 amp , but i cant see whats wrong with it being as it is.

also , i been told that you have to earth cable tray, i always thought that if it was rcbo protected you wouldnt have to do it , am i wrong?


cheers

They may have meant for you to feed this 25mm SWA via an 80amp switch fuse, rather than relying on the service fuse to protect it, presumable 100 amp???

 

[wellshocked]

im not too sure my mate said it come of the main busbar staright into a 100 amp fused isolator then out to the board,

 

[wellshocked]

i think this firm are being petty bout things , telling the client that it needs to be shutdown coz of this , apparently its been a massive drama

 

[Amp David]

im not too sure my mate said it come of the main busbar staright into a 100 amp fused isolator then out to the board,

If t is the case, ignore my post

 

[Dave 85]

i think this firm are being petty bout things , telling the client that it needs to be shutdown coz of this , apparently its been a massive drama

They sound like a bunch of c***s.
I was always taught (at college) not to bother earthing cable tray as, unlike trunking it only carries double insulated or armoured cable so is not an exposed conductive part. get the w***ers to show the clients the regs your pal is breaching in the book.

 

[johnboy6083]

i always bond tray ect.good practice,but i am aware that you dont need to.I dont bother with the silly links across joins though, when ive used joiners

 

[Amp David]

GN8 suggests not to also. Cables classed as double insulated.

This is from memory, so without actually looking I don't know if there are any other notes to add to this

 

[malcolmsanford]

25mm ok as 100 amps and just good practice to earth containment.

Why are you referring to tray as "containment" when it isn't ............look up definitions in the regs and it is a support it hardly contains things, so why are we bonding/earthing it ?

Is it because it is metal we feel we need to earth/bond it ?

 

[wellshocked]

cheers for everyones help

Been to the job today to help , blokes a nightmare, trouble is it was subbed out and the electrician firm who normally do the works there have tapped them up on everything, even the spacing of some cable cleats on one of the armoureds.

the client is standing toe to toe with the firm they normally use. gonna be a bit messy i think , got the client calling the niceic guys down .

there isnt anything wrong though, the only thing which could get messy is some air con units. they gotta 6mm armoured going to them and it has been earthed back at the board but not at the 32amp (plastic) isolator, personally i think its fine as there is also an rcbo protecting it. (i could be wrong though)

 

[Guitarist]

TBH, what has it got to do with the firm that didn't get the contract? Technically they shouldn't even be on site surely.

If the aircon units need earthing then there will be an earth terminal inside the plastic isolators to continue it on to the units. If the armouring is also being used then it can also be tagged inside or out and linked from 1 swa to another.

 

[wellshocked]

there single phase units , so it is live neutral earth on the inside of the cable anyway, when i looked it did have a tag but it is also earthed from the earthing terminal on the air con unit itsef. he left it out coz he didnt want to void the manufacturs warranty.

 

[wellshocked]

i meant he didnt terminate straight into the aircon units with a gland , because he didnt want to void any manufacturers warranty****

Basically this firm had to do a repair on a supply cable while the works was taking place and they started nosing about then and getting involved with the client.

they told her they need to look at the supply cable to the single phase distrubution board again as the calc wernt right.
25mm armoured, 100 amp isolator and main switch , roughly 25 - 30 metres ,clipped direct

3 phase db roughly only 10 circuits, lights, rings and a few air con.
on tray, 30-40 metre run , 125 amp isolater and main switch.

all sounds fine to me but causing him a load of greif,