some random questions about testing...

[ian.settle1]

ive been told its 2. it is 2 outlets.

Does that mean you count a twin fluorescent as 2 because it has two tubes?

 

[gamblor6]

fair point

 

[Deleted member 26818]

Originally Posted by Aaron123
Hi guys,

I've got alot of questions that i'd like to be answered.

1) Is a double socket counted as 1 point served or 2?I dont have the info to hand but it always used to be "each outlet counts as one point"...so a double would be two,this was for the pupose of establishing that the number of spurs does not exceed the number of outlets on the ring.....but for the puposes of a schedule of circuit details each point counts as 1...double or single.

I count it as one, and have read somewhere on here that its one, but a few people in work are adamant that its classed as 2. Is there any hard evidence that its classed as one that i can show them? What is the reason for number of points served?

Light switches? Are they counted?I count the number of loaded points...ie with a lamp...ignore switches.

PIR's? are they counted?As above

Spurs - do you count them or what they are feeding? or both?The spur point only

Isolator - do you count them or what they are isolating? or both?Isolator only...one point

Is there any documentation on number of points served? as it seems to be quite a few people including myself are unsure about it.Not that I am aware of...I've been doing as above for years without any comeback

2) PFC

Scenario: Lets say there is a pfc of 25KA at the mains which is protected by bs-88's, thats fine right. But then I have a pfc at a DB in that installation of 19ka, it is covered by 60898 breakers (10ka rating) I know these breakers would not be sufficient for the KA, but if that kind of fault current was flowing that the 60898 breakers could not operate the bs-88's at the mains would operate and cover the DB, so would that be a valid arguement that the board is covered?

Am I making any sense?



Outside Lights - they dont have to be covered by an rcd right? if they are out of reach fair enough, but what if it is low level surely it should be covered? it says in the regs that all mobile equipment for use outdoors is to be covered by an rcd, so spurs do not have to?In non special location situations on TN systems there is no requirement to provide rcd protection to fixed equipment outdoors..411.3.3



Periodic inspection:

Lets say the installation your testing does not conform to the 17th edition,

For instance if you have sockets that are not covered by an rcd, what do you do? does this mean it fails? Do you right it down as a recommendation? Or is it acceptable, because im guessing it conformed to the regs at one point...If that socket was liable to supply equipment outdoors or in another hazardous situation that would warrent a code 2....if it was not liable to supply equipment outdoors code 4.


No cpc on circuits, just trunking and conduit as an earth, is this ok? does it fail? do you right it down as a recommendation, because again at one point this conformed with the regs.As long as tests were satisfactory and the system was sound a code 4 might be appropriate

No rcd on circuits in bathrooms/swimming pools etc, is this ok? does it fail? do you right it down as a recommendation....bathrooms are only a recent requirement to rcd,you cant condemn all installs prior to 2008,so a code 4...swimming pool more serious as rcd protection has been a requirement for equipment in the zones for a long time,code 2 or even 1

This guy in work said that having live parts showing in the board (old c50 type) was a fault and he gave it a code 2? I said to him, its a board, it's meant to? Is he right? Surely not?As long as the live parts can only be accessed with a tool and the board was labelled "exposed live parts within" no code...if the live parts can be accessed without a tool code 2 or even 1 if in a situation where accessible to unskilled/unsupervised persons

Do sockets have to have a flying earth lead to the back box? I always do it, would you right it down as a fault on a new installation?As long as the socket has earthed metal screwholes and the box has at least 1 fixed lug...no......if there is no separate cpc(conduit earth)...yes.

Ceiling grid, does it have to be bonded? the lights that sit in it are earthed, would this be sufficient? No..it is unlikely to be an extraneous conductive part...see the definition of an extraneous conductive part in the BRB



I know its a lot of questions, but i would be grateful if anyone can answer them.

Cheers,
Aaron



...................

It's the NICEIC that counts double sockets as two points, but then again you're probablly using their test sheets.
Conduit used as CPC warrents no code at all, as it complies with current Regulations. Of course if Zs are too high that's another matter.
I would agree with everything else above.
I would point out, that the ESC and NICEIC do not consider the lack of RCD protection for special locations, warrents any code at all.

 

[IQ Electrical]

Yes, I agree with the conduit/trunking cpc point, it should not have a code applied if it meets the requirements of 543.2.2

It was mentioned briefly above but if conduit is used as the sole cpc then regardless of the lug-type on boxes, a fly lead MUST be used to the accessory 543.2.7

 

[Deleted member 9648]

Agree with second thoughts on the conduit point....you are quite right,no code if all tests are good.

 

[malcolmsanford]

agreed i may be wrong but i think, i cant find the paperwork, the niceic say its 2 points of utilazation ,spelling, on a circuit.

Would this be the same NICEIC that tells us an Installation Earth Electrode should not exceed 100ohms and the BRB states 200ohms

Could it also be the same NICEIC that tells us that "LIVE" testing should not be done and that Zs testing is preferably done by calculation.

It could even be the same NICEIC that says that to conform to regulation 522.8.1 when installing T+E into a flush mounted back box you have to use a grommit, and told people that the lack of them contravenes this regulation.

Most likley it's the same NICEIC that are pushing what IMO are totally worthless pieces of paper called something like "Condition Reports" to customer who believe that these reports are actually worth anything.

Not 2 worried what they think to be honest, I will be guided by the actual Regulations, not a schemes take on them.

 

[tonys]

When I sat my 2391 in 2000, I was taught by the head of technical at my local college. I asked the question, how many points is a double socket classed as, the answer was one point of utillization.

On the subject of ferrous enclosure being used as a protective conductor, the inspection and testing is a bit more involved than just using an ohm meter. Does an ohm meter prove the joints are capable of carrying a fault current? Should you inspect the enclosure along its length to verify its integrity?

At the end of the day, courses like the 2391 are there for a reason, more people need to sit and pass them.

 

[IQ Electrical]

Yes, 1 point per twin socket and inspect cpc containment along it's length in the absence of the high current continuity test (sometimes entertaining visual effects!).

 

[ian.settle1]

When I sat my 2391 in 2000, I was taught by the head of technical at my local college. I asked the question, how many points is a double socket classed as, the answer was one point of utillization.

On the subject of ferrous enclosure being used as a protective conductor, the inspection and testing is a bit more involved than just using an ohm meter. Does an ohm meter prove the joints are capable of carrying a fault current? Should you inspect the enclosure along its length to verify its integrity?

At the end of the day, courses like the 2391 are there for a reason, more people need to sit and pass them.

Problem is though that people who do not have the training or experiance are taking the course and failing the exam because they haven't a clue what they are doing which is shown by the constant low pass rate.

It may be contraversal but I think that is why there should be a structured system when taking courses and exams which should be enforced by all college and training centres, in that unless you have a prerequist or lower qualification you should not be able to take the next higher qualification without the lower one.

This is like when you do a degree (not counting mickey mouse ones or an OU degree) you can not normally get on one unless you have A levels or a HNC/HND

 

[IQ Electrical]

I take your point Ian but the problem is different people have a different aptitude to learning-do you force a quick learner to do a 2392 course before allowing him/her to take 2391-10/20 ?

It's all a bit namby pamby to me, there's enough information available from endless sources on the 'difficulty' of 2391-10 etc. If people are just booking onto courses without finding out how demanding the topic is then more fool them!

My training centre would make no such entry requirements other than 'payment at the little window please' .