Testing a lighting circuit fused down off the ring

[Jaywn]

Hi all.

When testing a lighting circuit fused down off the ring do I put it down on the test sheet as a separate circuit or mark it on the sheet that it's a spur?

Thanks.

 

[Deleted member 9648]

A spur.....it is part of the ring circuit for testing purposes.

 

[Tuttle]

I've also wondered about that because it's a bit like having another DB.

A B32 MCB on a ring would require a max Zs of 1.44 ohms where as a BS1362 13A fuse in an FCU would require a max Zs of 2.42 ohms for 0.4 sec disconnection.

Maybe it should have it's own test result sheet?

 

[Tuttle]

I asked a Part P assessor about this and he said that he would record the Zs for the ring on the test result sheet, as normal, and then note the Zs for the fused spur in the remarks

 

[telectrix]

well, he would as he's getting paid for being pedantic rather than having to get the job done.

 

[Tuttle]

well, he would as he's getting paid for being pedantic rather than having to get the job done.

What would you do then? (assuming that Zs on the fused spur is a fair amount larger than Zs on the ring, otherwise it's not worth worrying about).

 

[NickD]

What would you do then? (assuming that Zs on the fused spur is a fair amount larger than Zs on the ring, otherwise it's not worth worrying about).

Think I might called it a separate DB and fill out a separate Sched Of Tests. If it's really a fullish lighting circuit in its own right, Only takes five minutes to fill out a one-liner Sched Of Tests.

 

[NickD]

I asked a Part P assessor about this and he said that he would record the Zs for the ring on the test result sheet, as normal, and then note the Zs for the fused spur in the remarks

Not keen. Zs recorded in the box should be the max Zs for the circuit regardless, IMHO.

Indeed I think that would probably be a good way to fail your 2391/2/4/5. Are you allowed to fail your assessor? ;-)

 

[telectrix]

agreed. Zs should be read from the furthest point of the lighting spur. then if it's above the 1.44 for a 32A MCB, an explanatory note on the cert. mentioning the 5A 1362 fuse at origin of spur.

 

[NickD]

agreed. Zs should be read from the furthest point of the lighting spur. then if it's above the 1.44 for a 32A MCB, an explanatory note on the cert. mentioning the 5A 1362 fuse at origin of spur.

Nice one Centurion, like it, like it.

I wonder if NICEIC, ELECSA, NAPIT etc. all run around yelling SPLITTERS!!!!!! at each other?

<scene: the IEE, Savoy Place>
"We're NAPIT"
"We're ELECSA"
"We've come kidnap the President of the IEE, issue demands"
"So have we"
"We thought of it before you!"
etc.

 

[Tuttle]

agreed. Zs should be read from the furthest point of the lighting spur. then if it's above the 1.44 for a 32A MCB, an explanatory note on the cert. mentioning the 5A 1362 fuse at origin of spur.

And including the max Zs for the ring, I think, to show that disconnection times are met on the ring as well