An Awful Feeling This

[gap30]

R =1.83m/ohm/m at 20C for 10mm 45A load 80 metres length of circuit
R=m/ohm/m x Length / 1000
R=1.83 x 2 x 1.2 x 80 / 1000 = 0.35136
R= 292.8/1000
R=0.2928
R = rounded up to
0.3 ohms
vd = R X I
vd = 0.3 x 45
vd = 13.5v
max of 5% 11.5 v so 13.5v not acceptible as greater than max

this is from a post by brucelee, tbh i am struggling with getting my head around this one a little, i cannot get the sums to add up

 

[JUD]

Resistance of 10mm² at 20°C is 1.83mΩ/meter

Circuit load = 45A
Circuit length = 80m

Total resistance at 70°C = (mΩ/m x 2 x Ct x L) ÷ 1000
Total resistance at 70°C = (1.83 x 2 x 1.2 x 80) ÷ 1000
Total resistance at 70°C = 0.35Ω

VD = IR
VD = 0.35 x 45
VD = 15.75V
VD > 11.5V (5%) so not acceptable

The 292.8 figure is the resistance at 20°C (1.83 x 2 x 80 -- no correction for 70°C) and is not used when working out voltage drop.

 

[brucelee]

soory Gap this was the only one that threw a spanner in the works for me when i did the exam i only knew how to work volt drop from mv/A/m x Ib X L /1000

I knew it was to do with ohms law so worked it out best i could and endd up forgetting to use the 1.2 for increase in resistance due to operating temp

jud is correct the total resistance is 0.35136 rounded down to 0.35
Vd = IX R
Vd = 15.75v and is greater than the 5%value of 11.5v so is unacceptable
so you can either increase Csa of conductor shorten length which will be almost impossible lol

If you work it out without the 1.2 correction factor then you will come up with the answer i did

I spent ages on this in exam as really was stuck rest of the exam i had done in 1 hr 20 spent 20 to 30 mins on it then rest going over exam again and this again

mate you have brought it all bvack to me lol

Now I know how to do it correctly as i spent the next few days going over exam on forum until i was sure I had done enough

 

[rick.oshea]

Gap,

I'm not sure if this has been mentioned (as 27 pages of posts takes some time to read through.....I got to page 9!) but time management can play a major part in the exam and place unnecessary pressure on you. I remember the feeling well!! As a lot of the guys have said, getting you mind right is going to play a major part in getting this nailed this time around.

I remember last year when I did mine, the first 2 questions in section 1 fried my brain, which put me on the back foot straight away (I'm sure they do it on purpose, mind you). I ended up wasting time on questions in section 1 and rushed section 2 where the main marks are.

The scenarios in section 2 are more relative to the work we do day-in day-out I found, where marks in section 1 can sometime be down to getting the wording & terminology exactly right for C&G.

On the day of the exam, try starting with Section 2, getting that nailed and hitting the weighted part of the paper and tot up the marks and then do section 1. Unconventional, but is a good way to manage your time productively relative to the weighted marking. It was a tip that was given to me after the event and in hindsight, probably would have been a better approach.

I hope this exam tip helps & good luck mate...

 

[gap30]

i have hit a brick wall atm with my studying, still so much to absorb, still dont fully understand tt installations with resistances and rcds ie Ra, been looking at q.26 on march exam 100ohm therefore 50/100 = 0.5 - definately one area i need to brush up on

 

[Sparky Ninja]

Hows it going in here? I thought as IQ is on his 'hols' I'd pop in and lend a hand. You guys have done an awesome job so far. :clap:

 

[gap30]

Hows it going in here? I thought as IQ is on his 'hols' I'd pop in and lend a hand. You guys have done an awesome job so far. :clap:

as i said earlier for some reason i have hit a bit of a brick wall, one test paper i can fly through, others struggle like hell!

 

[Sparky Ninja]

as i said earlier for some reason i have hit a bit of a brick wall, one test paper i can fly through, others struggle like hell!

I've PM'ed you .

 

[gap30]

I've PM'ed you .

thanks

 

[brucelee]

Gap you will be ok mate you cant know everything but you can give it a go and as i have seen your doing enough mate

I put similar effort in and like you and was daunted at first.The more i read practised the more I started to understand, You think you wont know enough but I am sure you will.
I am sure you will find like I did because of all the study fly through it but take your time to read the quetions at least twice before rushing in
any your stuck on just move on and try to answer at the end
then read through it all if you have time until that cert drops on the floor you wont be 100% certain
But as you have put everything into it like me sure you will be OK

how long before the exam

 

[gap30]

Gap you will be ok mate you cant know everything but you can give it a go and as i have seen your doing enough mate

I put similar effort in and like you and was daunted at first.The more i read practised the more I started to understand, You think you wont know enough but I am sure you will.
I am sure you will find like I did because of all the study fly through it but take your time to read the quetions at least twice before rushing in
any your stuck on just move on and try to answer at the end
then read through it all if you have time until that cert drops on the floor you wont be 100% certain
But as you have put everything into it like me sure you will be OK

how long before the exam

11th August mate, brucelee can i run something past you mate

compile a list of 8 checks to be made during the inspection process that could apply to any type of electrical installation using any type of wiring system in any environment

now does this apply to 2.6.3 inspection checklist or,

2.6.2 comments on individual items to be inspected or,

the main headers on form 3

now after reading the question i am immediately thinking

connnection of conductors
identification of conductors
routing of cables within prescribed zones
basic protection
fault protection
selection of conductors for current-carrying capacity and voltage drop
presence of residual current devices
erection methods

but the ones i have listed are all from schedule of inspections, and the first two options i gave you are slightly different and go into more detail, i have almost memorised the schedule of inspections but am i right in thinking the question wants a bit more elaboration?

 

[Mark.W]

another one for you

state the purpose of an initial verification of a newly installed circuit

To conform that the circuit complies with the designers intentions
The circuit has been designed, installed and tested in accordance with the requirements of BS7671
It is not damaged so as to impair safety or otherwise defective

ok but guidance note 3 also says

initial verification shall be carried out to verify:

all installed electrical equipment and material is of the correct type and complies with applicable British Standards or acceptable equivalents
all parts of the fixed installation are correctly selected and erected
no part of the fixed installation is visibly damaged or otherwise defective

so which one is right?

The second part as per GN3 basically means that as part of an initial verification, these items should be inspected!

 

[brucelee]

mate your on the money as it asks for a list and for the first 20 questions its either a couple of wordsor a sentance at most

your answer is ok as its asking for a list like a shopping list so your on the mark and as long as applicable to any instalation then i reckon full marks for that answer
and from 2.6.2 these 19 items
and could be from also from pg 27 depending on situation and installation eg conduit then look down the general ist on pg27 see if any relevent then pg 30 for conduits

the 19 on pages 20 onwards are aplicable to all for initial verification
the ones from 27 depend on the installation either pir or initial

there is also a list for PIrs pg 66 3.9

the schedule ofinspections is the list from pages 20 - 26 they are the same and the C&G are testing your knowledge of the certs and GN3 also bs7671 so answer as per GN3 and your on the money


Iq or widdler may be able to explain better than me

 

[gap30]

mate your on the money as it asks for a list and for the first 20 questions its either a couple of wordsor a sentance at most

your answer is ok as its asking for a list like a shopping list so your on the mark and as long as applicable to any instalation then i reckon full marks for that answer
and from 2.6.2 these 19 items
and could be from also from pg 27 depending on situation and installation eg conduit then look down the general ist on pg27 see if any relevent then pg 30 for conduits

the 19 on pages 20 onwards are aplicable to all for initial verification
the ones from 27 depend on the installation either pir or initial

there is also a list for PIrs pg 66 3.9

the schedule ofinspections is the list from pages 20 - 26 they are the same and the C&G are testing your knowledge of the certs and GN3 also bs7671 so answer as per GN3 and your on the money


Iq or widdler may be able to explain better than me

yes mate i forgot about page 66 - so basically if i stick to schedule of inspections i am ok

 

[andybrock]

Gap you will be ok mate you cant know everything but you can give it a go and as i have seen your doing enough mate

I put similar effort in and like you and was daunted at first.The more i read practised the more I started to understand, You think you wont know enough but I am sure you will.
I am sure you will find like I did because of all the study fly through it but take your time to read the quetions at least twice before rushing in
any your stuck on just move on and try to answer at the end
then read through it all if you have time until that cert drops on the floor you wont be 100% certain
But as you have put everything into it like me sure you will be OK

how long before the exam

Excellent thread this guys.Taking my wriiten exam on the 11th Aug too so full into revision at the moment.
I'm on the course next week with my practical on Thurs.

 

[brucelee]

state the purpose of an initial verification of a newly installed circuit

To conform that the circuit complies with the designers intentions
The circuit has been designed, installed and tested in accordance with the requirements of BS7671
It is not damaged so as to impair safety or otherwise defective

ok but guidance note 3 also says

initial verification shall be carried out to verify:

all installed electrical equipment and material is of the correct type and complies with applicable British Standards or acceptable equivalents
all parts of the fixed installation are correctly selected and erected
no part of the fixed installation is visibly damaged or otherwise defective


as for this i was like you i thought eh 2 answers for same question but its not same

C&G will ask whats the purpose of initial verification according to Bs7671

Or initial verification carried out to confirm
M materialsof the correct type and comply with BS blah blah
E erected and selected properly
D damage and defects not present

I questioned out tutor on this and a few other things lol as we had a booklet they give us which had errors i spotted
he was a good tutor and always willing to help tried to add the answers he gave but cant sus out how to do it since the forum changed

 

[Sparky Ninja]

I'm halfway through looking at the paper Gap. I've checked part A and there is probably only 2 marks out of the 60 that I would consider knocking off. I'll finish going through it in the morning and then get back to you with the feedback.

 

[brucelee]

yeah mate but they may ask about a certain installor initial or pir installation eg conduit or trunking whatever then look at p20 onwards for initail and 27 onwards also if for pir pg 27 onwards and pg 66 etc

 

[gap30]

I'm halfway through looking at the paper Gap. I've checked part A and there is probably only 2 marks out of the 60 that I would consider knocking off. I'll finish going through it in the morning and then get back to you with the feedback.

cheers mate thats good to hear!

 

[gap30]

Excellent thread this guys.Taking my wriiten exam on the 11th Aug too so full into revision at the moment.
I'm on the course next week with my practical on Thurs.

you with me on the 11th pal, you stressed out as well lol

i had one of them days in work today lol, grafted all day just got in now, now i got to eat then more revision noooooo!