On the dreaded 2394 - 2395 Course

[Chris Harrison]

Hi all New to the forums but been working in the industry for 10 + Years now have my level 3 and 17th edition. Employers just put me on the inspection and testing course, not sure what to think at this moment on my second day. Initial letter says 5 days but looks like after this week will have to go in for a further two more tests, seems like they throw quite a lot of content your way in such a short amount of time.
I like to think i have had a lot of experience with testing and inspection, done quite a few periodic inspections with 30+ Distribution boards and probably the most experienced in the class but i'm still bricking it!
Was wondering what these qualifications will actually mean for me or allow me to do if anything extra, i don't see what my employer gains from sending me on this course?

P.s. I don't think city and guilds know what they are even talking about sometimes, get this sample question for instance:

Increasing the length of a cable would NOT affect the;

a. Voltage Drop
b.loop impedance
c.rating of the protective device
d.insulation resistance

C&G's correct answer was C announced the tutor! I don't have high hopes for the real life test where i can put in the 100% correct answer only for it to be wrong.

 

[happysteve]

C is the correct answer, though... (in theory, anyway). Longer cable increases the VD because V=IR and R will be bigger (more cable). The loop impedance will be bigger for the same reason. And the IR will be lower as you've got more insulation in parallel. How can putting a longer cable in change the rating of your fuse/circuit breaker? So C is your answer.

It is a lot of info to take in over 5 days. If you've been doing it for 10 years, you will be well up to speed on the techniques and practical aspects. What you'll have to get your head around is calling everything by its proper name. It's not a megger, avo, or even a continuity tester: it's a low-resistance ohmmeter.

Read GN3 cover to cover. Then repeat.

Good luck

 

[Taylortwocities]

I read the question, and my answer is also c.
The critical word in the question is NOT.
If you increase the length of a cable then a, b and d are all affected.

C&G often word their questions in an obtuse way, so you gotta read it carefully!

 

[happysteve]

C&G often word their questions in an obtuse way, so you gotta read it carefully!

They do! They go on a special technical course on how to set questions in such a way that you can't skim-read them, you have to read them carefully and work out what exactly they're asking.

It's called the "sneaky gits" course, I believe...

 

[Chris Harrison]

Long discussions with the tutor and we have both come to the conclusion that C&G's are sneaky buggers for there wording yes!

 

[Paul.M]

D. is the correct answer.

Cable length could be 1m or 200m. It is testing the insulation resistance, not the length of the conductor. The other options are all related to length of conductor!?!?!?!?!?! Although the option are all related, the key word is """NOT"""

 

[Silly Sausage]

Straightforward question, apart from the negative aspect of it. That's there to make you stop and think for a second!
It is clearly C.
Ask yourself why it's not A,B or D.

 

[Leesparkykent]

yep clearly C.

 

[Taylortwocities]

D. is the correct answer

Nah

If you have a 200metre length of cable, the IR will be more than a 1metre length. Not by much, but it will be more.

 

[Leesparkykent]

Nah

If you have a 200metre length of cable, the IR will be more than a 1metre length. Not by much, but it will be more.

less?

 

[Taylortwocities]

oh yes, less Megohms. Bloomin' Merlot......:bananas:

 

[Paul.M]

Increasing the length of a cable would NOT affect the;

a. Voltage Drop
b.loop impedance
c.rating of the protective device
d.insulation resistance

C. """affects""" the choice of the OPCD due to A & B. Insulation Resistance will not be effected due to the length of the cable!

Time loop impedance "affects" the designed OPCD due to length of the cable run. The answer is still D in my book. (Tin hat on)

 

[Silly Sausage]

I'm making no further comment as I'm not a Trusted Advisor!

 

[Paul.M]

I'm making no further comment as I'm not a Trusted Advisor!

You should be

 

[Leesparkykent]

The longer the cable the lower the insulation resistance.

 

[Dan]

I'm making no further comment as I'm not a Trusted Advisor!

You should be

That's not how it works.

 

[Richard Burns]

I would say that if the question were saying "if you only increase the length of cable what does not change?"
Then the rating of the protective device would not change as you have not changed it!
The choice of protective device may be altered by the maximum EFLI permitted for that device.
Volt drop increasing may limit your design current, not necessarily the choice of protective device.
Increasing the cable length would increase the surface area of conductors in close proximity and so will reduce the insulation resistance. This is similar to testing one circuit alone vs. testing multiple circuits simultaneously, though the resistances are parallelled in the multiple circuits scenario and so make a larger difference. However for a new cable the result may still be off scale in both cases. C is certainly the C&G answer!