Swa current carrying capacity

[davesparks]

I see by your wonderful post that teaching people new things just isn't your style...

I am more than happy to teach new things, but I don't think I can put enough information in to a post on here to explain this properly.

 

[fattony]

It's a strange setup this, I'm doing the work on behalf in the managing agent so only looking at landlords side, there is another sparks working for the fit out company and for some strange reason they didn't want him to take on all the works.

I wanted to pull the cables back through the galvtrunking on the 2nd floor and get a hole through the floor (builders works) dropping into the board in copex, told no holes through the floor.

So we ran 24 circuits through the first floor, up the riser to the existing db location for a junction box, din rail connectors

Literally about to start stripping out the db ready for the junction box to be told that there is no room for a junction box in the riser and I should have pulled the cables back through the 2nd floor, ffs!

Fortunately client is on my side this route was discussed and agreed but I've got to pull it all out and start again.

In the new db the other sparks was intending on fitting a meter, I have now found out the 16mm swa is a sub main off another board hence the meter, the meter looks like it needs a connection for power but I'm not sure where to connect it, are they fuses on the bottom right and I need to come off the main switch?

View attachment 35397

 

[Leesparkykent]

It's a strange setup this, I'm doing the work on behalf in the managing agent so only looking at landlords side, there is another sparks working for the fit out company and for some strange reason they didn't want him to take on all the works.

I wanted to pull the cables back through the galvtrunking on the 2nd floor and get a hole through the floor (builders works) dropping into the board in copex, told no holes through the floor.

So we ran 24 circuits through the first floor, up the riser to the existing db location for a junction box, din rail connectors

Literally about to start stripping out the db ready for the junction box to be told that there is no room for a junction box in the riser and I should have pulled the cables back through the 2nd floor, ffs!

Fortunately client is on my side this route was discussed and agreed but I've got to pull it all out and start again.

In the new db the other sparks was intending on fitting a meter, I have now found out the 16mm swa is a sub main off another board hence the meter, the meter looks like it needs a connection for power but I'm not sure where to connect it, are they fuses on the bottom right and I need to come off the main switch?

View attachment 35397

Sounds like a right pain in the backside job mate.

 

[fattony]

Sounds like a right pain in the backside job mate.

It is, wish I never got involved, I've had to connect the swa to a temp board for now, when they fit the new board they will re terminate my swa, I could pull 3 circuits back through the first floor but I'm not touching the 2nd floor without another order, will test what I've done and close the job as far as I'm concerned, once they've argued it I'll go back and change it, means this will get stripped out though

View attachment 35398

 

[Chr!s]

hi

I've been asked to pick up a job where the previous builder went into liquidation and the property management company is asking me to complete the electrical works, relocate a fuseboard.

Everything the previous company has done is exceptionally neat but I'm concerned on the design front with the SWA, the supply from the mccb panel is 100A and the new swa they have pulled in is 16mm 4c (TPN) looking at the guides on the web current carrying capacity for this clipped direct is 94A, struggling to remember the exact formula would have to go through the books but is the 94A a guide and you can calculate it exactly?

Would rather not derate the mccb, and it's virtually impossible to rewire without taking ceilings down

Thanks

Hi, id suggest probably okay, the designer may have tweaked the factors applied to the cable ccc, if so you can get it above the 100 amp.

 

[westward10]

Looks like it should connect to L1, L2 and L3.