Electrical installation design guide

[mickfred]

1capybara are you agreeing or disagreeing with me regs speak goes over my head sometimes unless I read it 10 times

 

[Pete999]

Don't. Know how to pm . my email address is [email protected] ta

Did you get my email?

 

[mickfred]

Just checked now . Ta Pete appreciate it

 

[davesparks]

Had a look online and basically any cable over 70mm doesn't have the CSA of armour to be used as a CPC, might be looking at a obsolete table

Whenever you got that information from is wrong, if you do the calculation you will find that almost every size of SWA is fine.

 

[bigspark17]

Are you not getting confused as to when the armouring would need to provide equapotential bonding in an EMT.? Maybe you could give more detail about your install.?

 

[1capybara]

At the end of the day, If your inspector is ok with it, using the
SWA as CPC is functionally adequate, research and actual use shows. However, if your inspector says not allowed,
then its not allowed. There is no clear direction in the code. What Pete posted says
"This table is intended purely as a guide only and is ….
not to be used as a substitute for proper cable calculation and circuit design"
and what I posted is "research only."

 

[mickfred]

Well , am upgrade a (45m)95mm 4core to a 120mm4core as the supply is 315amps probably more in the substation , the information comes from table b1 guidance note 8 . But this come up in the thread where it was said the all swa cables armour is good to go to be used as a protective conductor . The original question was about a table in the design guide witch said it was cool to put 500a fuses to protect a 120mm cable . This a thought may have been a mistake or could have been saying that the armour could take the fault to blow a bs88 500v Fuse

 

[mickfred]

The 95mm i put in 4years ago has good reading (can't tell you what they are off the top of my head). It just my div of a boss keep buying machines with out telling me and after moaning that this cable need up gradeing so we can use more of the supply ,he has put his hand in his pocket , iwas just double checking today to make sure that i didn't have to run a separate CPC or get 5core or start bonding the frame work to get the efli before he brought it . Ps can anyone tell me how to put up quotes because it looks like am responding to different post than i am thanks

 

[Wilko]

If you hit the quote or reply button on the post you want to comment on it will all happen for you

 

[mickfred]

Ta wilko .gorillas are great , don't like chimps they like to pull people faces off (too much sugar in their tea I think )

 

[Wilko]

You mentioned bonding in #23 and if you need bonding then swa armour may not be up to it. How is the site earthed? And can you id the table with the 500A ref?

Edit : Agree, the 120mm 4 core has plenty of armour for cpc

 

[mickfred]

Don't need bonding , was just make sure that was the case , that's all . the table that raised the original question was table 8.8 in the design guide page 100 ( maximum bs88 fuse sizes for multi core armoured cables having thermosetting insulation (copper conductors) when as armouring is to be used as the protective conductor .sizes endorsed in table 4e4a of bs7671 ) . I know its a snappy title

 

[mickfred]

If you hit the quote or reply button on the post you want to comment on it will all happen for you