June 2011 2391 exam

[Richard]

Did any of you sit it? I didn't think it was TOO bad, couple of questions I was a little unsure of but overall ok. How did you guys find it? I can never think of the bloddy questions afterwards!

 

[dean7828]

the type of test is pereodic inspection and test not pereodic test, its all about terminolagy also i think it makes no difference how easy the paper is as i was told that a national average is taken and then they slot everyone in arround the average, so if everyone found it easy they have no more chances of passing as if everyone found it hard. seems strange to me but its all to do with employer feedback, they want people with a certain mentality.

 

[72-van]

Yes the way the do the pass arrangement is not as we normally have it north of the rio tweed.

It would be much easier to say get 70% of the marks and you pass or whatever score they deem should be the case.

surely somebody can remember some questions ?

72-van

 

[dean7828]

Can any one remember any of the other questions ?

discribe what you would check for on the pvc conduit and trunking

discribe 4 items to check for on the armoured installation useing the sense of touch

discribe the insulation resistance value effects on between live conductors on a switched sput containing neon lamp switched in the off position

explain why the dno cant give values on a tt system

what earthing arrangment applies to external earth fault values of 0.35,0.8,21 ohms

cant think of anymore

 

[dean7828]

name 3 reasons to check polarity

 

[kennydeeee]

Why the sockets in the community centre required rcd protection

 

[72-van]

Yes ...what was the right answer to the plastic conduit one ??

 

[72-van]

what was the right answer to the rcd socket one ?

i put something like bs7671 req all sockets for use by ordinary persons to be rcd protected

 

[kennydeeee]

Polarity all switches fuses and single pole devices connected in the line conductor only- ensure centre contact of Edison screw lampolders connected in the line conductor only exception e14 and e27 - ensure all sockets and accessories are connected correctly

 

[kennydeeee]

Community centre is for the use by the general public (ordinary persons) so sockets would require additional protection hope I got a mark for this

 

[NEV]

Polarity all switches fuses and single pole devices connected in the line conductor only- ensure centre contact of Edison screw lampolders connected in the line conductor only exception e14 and e27 - ensure all sockets and accessories are connected correctly[/QUOTE

Did you answr the question on the containment system? Was this referring to the check list in GN3 on trunking and conduit.

 

[kennydeeee]

The ka rating on the mcb think I said to change for a mcb with a higher breaking capacity

 

[NEV]

discribe what you would check for on the pvc conduit and trunking

discribe 4 items to check for on the armoured installation useing the sense of touch

discribe the insulation resistance value effects on between live conductors on a switched sput containing neon lamp switched in the off position

explain why the dno cant give values on a tt system

what earthing arrangment applies to external earth fault values of 0.35,0.8,21 ohms

cant think of anymore

What inspection is to be carried out on a severely over loaded installation
What areas would you be most concerned with during the inspection.

 

[kennydeeee]

I answered check properly fixed using sence of touch ( give it a shake ) ensure all lids are in place visual inspection correct position and number of boxes for easy draw of cables visual inspection not sure if that was the Answers they where looking for but thats what they got lol

 

[kennydeeee]

For this one periodic inspection check maximum demand cables selected for current carrying capacity and volt drop bound to be worth 1 mark

 

[Richard]

As many are talking about the volt drop question the correct answers were: 3% for lighting from a public distribution system (so 6.9V of 230V), 8% for the 3 phase motor supplied from a (private) factory generator (so 32V of 400V, I think it was 400V), 5% for the immersion heater in a domestic home (supplied from a public distribution system so 11.5V of 230V). I think I remember these in order. Percentages for volt drop can be found in appendix 12 of BS76 71 Table 12A

What made you think it was supplied by a private generator?

 

[72-van]

i bet they wanted an part answer saying that it was securely fixed to the wall with adequate clips and supports...pity i never wrote that ..

 

[joe_berks]

i put check ends are bushed and reamed , radii of bends for conduit. protected against mech. damage. securely fixed.

IR i answered 'no effect'

earthings arrangement i said tn-c-s , tn-s and tt

what do you think is that right ?

 

[SirKit Breaker]

think i got the voltage drop calcs for the motor circuit up put 5% but think its 8% how long dose it take for the results to come through

6 to 8 weeks mate. hope you passed i know it is tough.

Cheers..........Howard

 

[joe_berks]

in regard to the question 'what two test currents on a 100mA RCD' i answered 1x and 5x ... well just looked at my tester (fluke 1653) and set to 100mA . doesnt give an option to test at 5x so that answers that one . thing is though, when i select 1000mA RCD , i can test that at 1/2x or 1x !!!

 

[72-van]

I might be wrong but dont you only need to do the 5 times test when you are testing a rcd/rcbo giving additional protection .so I delta N value of less than or equal to 30 ma ..

72-van

 

[IQ Electrical]

I might be wrong but dont you only need to do the 5 times test when you are testing a rcd/rcbo giving additional protection .so I delta N value of less than or equal to 30 ma ..

72-van

You're quite correct.

 

[72-van]

Yippee got an answer right

 

[sparks_114]

What made you think it was supplied by a private generator?

From what I recall it said factory generator so I read that to mean private which'd be 8%. I hope I'm right?

 

[kennydeeee]

Did anyone manage to sneak out an exam paper

 

[72-van]

Not me !

but any other non c&g exam i have done in my life they allow you to take the paper away so that you can assess how you done .

 

[kennydeeee]

This wait for the results is gonna destroy me gonna get my head stuck into the pat testing maybe do that to keep me sain

 

[72-van]

Mate once you start doing Pat in the field its the other way around you 'll need something to be thinking about when your doing the Pat its mind numbingly boring repeatative and wholly unsatisfying .

One recommendation i would give anyone starting out -- get some good kneepads

If you need a help with the Pat stuff feel free to ask
I have just done the c&g after doing the work in the field for years.
Get a copy of the Cop if you dont already have it and memorise
Its a multiple choice exam ..what out for sneaky questions double negatives etc.
Loadsa questions which have absolutely no relevance in the field and precious little practical time on the testers.

72-van

 

[abingdonjon]

I have a copy of Thursday nights paper if somebody knows how i can add an attachment (PDF) to these threads? Not to clued up on computers unless its fairly straight forward.

 

[NEV]

I think there's a ban on publishing past papers on the forum, however could you send me a copy by email?

 

[abingdonjon]

ok, no worries. I'll just reel off a few questions then and try to mark my own paper. Thought it was quite a straight forward paper compared to some practice papers.

 

[abingdonjon]

Q2.
An installation has been seriously overloaded and requires investigation. State

b)
two areas which require close inspection as a resuit of the overloading?

I answered Distribution board and Wiring. Don't know if wiring is acceptable terminology?

 

[abingdonjon]

Q5)

State three inspection checks that may be carried out on an armoured cable installation using the sense of touch?

Any answers?

Q11)
State the effect on measured values of insulation resisLance of a230 V circuit if an​

insulation resistance test is carried out

i) between live conductors to earth with a tungsten lamp in circuit

ii)between live conductors with a switched fused connection unit, having a
neon indicator. left in the off position.

Any answers?

 

[abingdonjon]

Q14) State the minimum degree of lP code protection to be afforded by the

a) front surface of a distribution board?......IP2X?

b) horizontal top surface of a motor starter which is accessible?......IP4X?

c) front surface of a conduit box contain ing live terminals?......IP2X?



Q16) State the test instrument to be used to carry out a resistance measurement of an earth electrode

a)that forms part of a TT system that ls protected by a 100'mA RCD? Earth fault loop impedance tester?

b)used to earth a three phase transformer? Earth fault loop impedance tester?

c)used to earth a generator? Earth eclectrode tester?

 

[kennydeeee]

Yeah some1 got the exam paper out please please please email it to me [email protected]

 

[kennydeeee]

Yeah some1 got the exam paper out please please please email it to me [email protected]

 

[Jurasic Spark]

Q5)

State three inspection checks that may be carried out on an armoured cable installation using the sense of touch?​

Any answers?​

Q11)
State the effect on measured values of insulation resisLance of a230 V circuit if an​

insulation resistance test is carried out

i) between live conductors to earth with a tungsten lamp in circuit

ii)between live conductors with a switched fused connection unit, having a
neon indicator. left in the off position.

Any answers?

i) The instrument would display a dead short, reading through the filament.
ii) In the off position it would not effect the reading.

 

[Jurasic Spark]

Q14) State the minimum degree of lP code protection to be afforded by the

a) front surface of a distribution board?......IP2X?

b) horizontal top surface of a motor starter which is accessible?......IP4X?

c) front surface of a conduit box contain ing live terminals?......IP2X?



Q16) State the test instrument to be used to carry out a resistance measurement of an earth electrode

a)that forms part of a TT system that ls protected by a 100'mA RCD? Earth fault loop impedance tester?

b)used to earth a three phase transformer? Earth fault loop impedance tester?

c)used to earth a generator? Earth eclectrode tester?

b) Earth electrode resistance tester

 

[Jurasic Spark]

Q5)

State three inspection checks that may be carried out on an armoured cable installation using the sense of touch?

Any answers?

​

SWA adequately supported so as to avoid any mechanical stress.
Steel wires secured into gland and effectively connected to earth.
Glands tightened correctly
Shroud fitted over gland correctly
Connection of conductors​

 

[kennydeeee]

Cable not overheating feel
Temperure with hand

Check glands are secure shake with hand

Ensure Terminations are tight using suitable screwdriver

 

[IQ Electrical]

Originally Posted by abingdonjon
Q5)

State three inspection checks that may be carried out on an armoured cable installation using the sense of touch?

Any answers?

Q11)
State the effect on measured values of insulation resisLance of a230 V circuit if an​

insulation resistance test is carried out

i) between live conductors to earth with a tungsten lamp in circuit

ii)between live conductors with a switched fused connection unit, having a
neon indicator. left in the off position.

Any answers?

i) The instrument would display a dead short, reading through the filament.
ii) In the off position it would not effect the reading.

Is that exactly how the question was written in i?

'Between live conductors to earth' could mean between L+N joined together to earth in which case the lamp would have no effect.

Not that I'm in any way suggesting ambiguity in a City & Guilds question!