need to pick some brains.

**madeinengland** · 08-06-2009

got some homework due in tomorrow and i can't find some of the answers anywhere in osg or regs book.

1) how do you test metal conduit for continuity?

2)what is the relationship between resistence values for live and earth cables in a ring?
how would a spur effect test readings.

3)where does it say about making good after installing cables in walls?

answers please or pages to find answers in regs book

cheers guys.

**JASON** · 08-06-2009

Have you looked in GN3??

**Guest123** · 08-06-2009

1. By carrying out an R2 test

2. In a 2.5/1.5 ring circuit the resistance end to end of cpc's will be 1.67 times as much as the lines and neutrals.

3.??

**scotsparky** · 08-06-2009

I will give you some pointers as a hint but not giving answers (heard that before)

1, Regs section 6, OSG section 9, or GN3
2, OSG section 9, GN3
3, Regs section 5 560.10

**Guest123** · 08-06-2009

Sorry Scot.

I left him one to work out.

**madeinengland** · 08-06-2009

cheers guys don't have guidance note 3 yet though.

scotsparky. you sure it's 560.1? think i'm missing something.

**scotsparky** · 08-06-2009

pritty sure after installing a cable you have to resore any fire protection around a penetration 560.10 is a rough guide i used it as a glance at the BRB. after a better look i found this 527.2

**madeinengland** · 08-06-2009

got it. nice one scotty!
cheers

**Andy Smith** · 08-06-2009

Originally Posted by lennytheloon

Sorry Scot.

I left him one to work out.

Oh you task master you

**madeinengland** · 09-06-2009

sorry to be a pest lads but i'm still unsure about my 2nd question.
what is the relationship between resistence values for live and earth cables in a ring? how would a spur effect test readings?
the first part i get as the difference in conductor sizes mean different resistence values. i don't have red osg or gn3. how would a spur effect the test readings?

**scotsparky** · 09-06-2009

As the spur is an addition to the ring and only 1 single conductor it will be a higher resisitence.

**Guest123** · 09-06-2009

Hi.

If you were carrying out an interconnected R1+R2 test and testing at each socket outlet then the readings would be substantially the same for all sockets that were on the ring circuit.

At the spur however the reading would be uncharacteristically higher than all the other readings due to it being spurred off the ring and not part of the original loop i.e single conductors.

Hope this makes sense to you.

**madeinengland** · 10-06-2009

cheers lads. unfortunately home work was in before i saw this thread but now i'll know in the future so nevermind but thanks for all your help. also did my 303 fault finding and rectification practical exam yesterday and got a credit (woohoo!). 3 exams down 2 to go.