radial spurs

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Lee321

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i think we all have in the past spur'd/tee'd of a radial

but what is the letter of the law?

especially lighting circuits when trying to reduce the number of cores at light points etc due to light type and there measily sized cable entry/routes/terminals etc

how would you report that at testing time having 2 ends of the circuit?

 

Lee321

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so a radial can have spurs?

and a lighting circuit can have 2 ends?

 

Lee321

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but we try to keep the circuit normal i.e feed in and out at each light point as say a 3 plate in domestic so there is only ever 2 neutrals at each point with the exception of 3 were a loop switch wire is going to secondary light in a single room,

but if we have several " T's " and several ends of the circuit then where would you call/test "end of circuit" for ELI

 
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but we try to keep the circuit normal i.e feed in and out at each light point as say a 3 plate in domestic so there is only ever 2 neutrals at each point with the exception of 3 were a loop switch wire is going to secondary light in a single room, but if we have several " T's " and several ends of the circuit then where would you call/test "end of circuit" for ELI
where do you call the furthest point of a RING circuit.

As KME says..

HIGHEST reading is the furthest point... ring OR radial. ;)

 

Lee321

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where do you call the furthest point of a RING circuit.As KME says..

HIGHEST reading is the furthest point... ring OR radial. ;)
correct but i was on about radials.

on a periodic you might not discover that a lighting circuit has several ends !

you would wrongly assume that the light at seemingly the furthest point/distance is the end then when you open the fitting and discover only 3 cables would satisfy you?

 
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i think we all have in the past spur'd/tee'd of a radialbut what is the letter of the law?

especially lighting circuits when trying to reduce the number of cores at light points etc due to light type and there measily sized cable entry/routes/terminals etc

how would you report that at testing time having 2 ends of the circuit?
Have you looked at example "radial circuits" on page 363 of the big red book...

radial just means it doesn't come back to the origin..

NOT whether it branches or not..

 
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correct but i was on about radials. on a periodic you might not discover that a lighting circuit has several ends !

you would wrongly assume that the light at seemingly the furthest point/distance is the end then when you open the fitting and discover only 3 cables would satisfy you?
The highest one (`cos you`ve tested them ALL
NOT a joking comment, mate. You should have tested EVERY outlet, socket, light, fixed appliance, etc

how else would you know if a fitting was switched neutral, for instance????

 

Lee321

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NOT a joking comment, mate. You should have tested EVERY outlet, socket, light, fixed appliance, etchow else would you know if a fitting was switched neutral, for instance????
10% rule?

 

Lee321

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i read on here very very recently (wrongly or rightly) that if when testing your 10% results are high? further investigation/testing is required?

that would suggest that only 10% of fittings of a circuit be tested?

i'm here to learn ;)

 
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could you "post the post" please?

I`d be interested to see where that was said ( I don`t remember seeing that!)

Don`t just take my work for it though. I`m sure SL and a few of the other regulars will put there thoughts in here.

KME

 
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correct but i was on about radials. on a periodic you might not discover that a lighting circuit has several ends !

you would wrongly assume that the light at seemingly the furthest point/distance is the end then when you open the fitting and discover only 3 cables would satisfy you?
NO you wouldn't

You don't ASSUME anything!

I believe you will find guidance suggests that..

where no drawings / charts / tables / schedules

give details of circuit layouts..

then a thorough investigation is requires to establish the circuit arrangements!

obviously on a rewire.. you know what you have put where and where the ends are.

and you will fully document this for future reference by others at a later date if required...

i.e that is to ensure compliance with 514.9.1 Pg 93!

also I believe first paragraph of 3.8.1 guidance note 3 (thats the old version haven't got my 17th copy yet!)

states exploratory work necessary prior to inspection to ascertain composition of circuits.. this would include FURTHEST point IMHO!

Of course if you know there are NO charts drawings etc.. available..

then you allow extra in your cost for doing the PIR!! ;)

;) :D

 
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i read on here very very recently (wrongly or rightly) that if when testing your 10% results are high? further investigation/testing is required?that would suggest that only 10% of fittings of a circuit be tested?

i'm here to learn ;)
You open up a sample...

for an internal inspection

3.9.1 (d) page 71 GN3

But still TEST all your furthest points!!! :D :) ;)

 

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You open up a sample...for an internal inspection

3.9.1 (d) page 71 GN3

But still TEST all your furthest points!!! :D :) ;)
thats what i was trying to say but you worded it better.

so a fitting with reversed polarity could go missed (kme ;) )

 
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NO, mate, it couldn`t.

If we`re talking a PIR, how would YOU know which point ( bearing in mind the length of cable to/from the switch(es) is included) was the furthest, on any given circuit?

How would you know if a ring was bridged, unless you had taken readings from all points; or indeed, if ring had multiple spurs.

Tell me then, please.:

How do YOU test a PIR, and find the furthest point (r1r2) of a circuit????

n.b. If YOU missed a fitting with reverse polarity, :

1. How can you tick the box which says "All single pole switches are in the phase conductor"?????

2. What will your defence be if, as and when someone changes a bulb, with the switch off, and ends up dead on the floor????

I anticipate your reply!

 
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