Assignment help!

[Graham Coughlan]

I dont know if this is in the write place but forgive me if its not....

Ive got 2 questions im stuck on if anyone could help please.

1. An insulation resistance measurement taken at theorigin ofthe installation records a value of 1.95mohms. Explain your subsequent actions regarding this vaule of IR

2. In order to comply with BS7671 the instrument used to measure IR must me capable of delivering a current of 1mA. Explain the reason for the requirement.


Thanks

 

[Plonker 3]

What do you think the answers should be? Not having a go but surely if you tell us what you think then at least we point out where you are going right or wrong. After all you wont learn anything if you are just given the answers will you?

 

[needasparks]

I'm not going help you on this as I feel you should be able to work this out from the question and we won't be there for you when you do your exam, However you should have been given Minimum values on an installation and the requirements of a test meter.
I don't know what books you have available to you but all the answers are in bs7671 and GN3. Good luck

 

[Engineer54]

What do you think the answers should be? Not having a go but surely if you tell us what you think then at least we point out where you are going right or wrong. After all you wont learn anything if you are just given the answers will you?

I'm not going help you on this as I feel you should be able to work this out from the question and we won't be there for you when you do your exam, However you should have been given Minimum values on an installation and the requirements of a test meter.
I don't know what books you have available to you but all the answers are in bs7671 and GN3. Good luck

Guy's he's not a student taking electrical training, he's a ''hospitality'' student so he will have No electrical knowledge at all... The questions being asked, are outside most peoples understanding, without electrical knowledge...

 

[Plonker 3]

This thread says otherwise

http://www.electriciansforums.net/i...tions/51125-how-calculate-pfc.html#post459002

 

[needasparks]

Yes i flicked back through also.

 

[Ringo]

Graham, I reckon the thread Dillb linked to above could be of some use with at least one of these questions!

 

[Graham Coughlan]

Ive got access to GN3 and a copy of 7671 which lets just say i got by other means...

GN3 points me towards 713-04-03 but for some reason the copy of 7671 seems to skip section 713 all together, in fact it jumps from 712 to 717 so either i'm missing something or i'm miss-understanding what this reference number means.

 

[Ringo]

Ive got access to GN3 and a copy of 7671 which lets just say i got by other means...

GN3 points me towards 713-04-03 but for some reason the copy of 7671 seems to skip section 713 all together, in fact it jumps from 712 to 717 so either i'm missing something or i'm miss-understanding what this reference number means.

???? What page in GN3 are you looking at?

 

[Graham Coughlan]

page 85 section 4.4

 

[Engineer54]

Sorry guys, it seems i got confused with another thread i'd just read...lol

 

[Ringo]

Hang on a minute, that's 16th edition numbering, surely?

I think you might need to get a copy of GN3 by other "other means". Not meaning to preach, but I got mine using money....

The whole piracy issue is a grey area in my opinion, but if you're going to use "other means", it's down to you to be sure you've got up-to-date publications.

 

[Graham Coughlan]

What do you think the answers should be? Not having a go but surely if you tell us what you think then at least we point out where you are going right or wrong. After all you wont learn anything if you are just given the answers will you?

I'm not going help you on this as I feel you should be able to work this out from the question and we won't be there for you when you do your exam, However you should have been given Minimum values on an installation and the requirements of a test meter.
I don't know what books you have available to you but all the answers are in bs7671 and GN3. Good luck

Okay, am i right in saying that an ideal IR result should be >1mohm as you want the lowest resistance possible so something is right. I know that frayed and scored cables can cause more resistance so one thing to do would be check all the cable ends to make sure theyre all twisted and bent over. Cable sizes should be checked to make sure they are the right size and have no damage to them.

For question 2

what i can gather is that its something to do with SPDs and anything higher than 1mA may damage the protection device but not every installation has an SPD so theres got to be more to it than that..?

 

[Plonker 3]

Question 1 is answered in GN3 and question 2 is answered in BS7671, took me about 5 minutes to find both answers.

 

[Graham Coughlan]

Hang on a minute, that's 16th edition numbering, surely?

I think you might need to get a copy of GN3 by other "other means". Not meaning to preach, but I got mine using money....

The whole piracy issue is a grey area in my opinion, but if you're going to use "other means", it's down to you to be sure you've got up-to-date publications.

I dont have access to a lot of money and definitely cant afford the £70 for the 7671 but yeah it was 16th edition numbering the one i needed was 612.3