Hi,
This is my first post, although I have been browsing the forums for a little while now.
I work in BMS and have my AM2 on friday. The nature of my work means I don't get to test so there are a few things I'm unsure of and was hoping for some clarification.
I know for some people they may be obvious but I don't want to make any small mistakes and I want to be as prepared as I can be.
I know its a lot of questions but I'd be grateful with whatever people can clear up, specifically on the I.R tests.
General
1. Does the banjo bolt at the cu go inside and face out of the cu
2. does the SY between the DOL and motor only need to be banjo'd at one end as its for interference and not earthing?
Testing Sheet
1. would the AM2 bay be best classed as industrial or commercial so I know how long to put the next inspection due in part.
2. When I measure Ze I know to put the figure down as Zs at DB but on the installation certificate can i put this down too, as its so close to the main incoming supply it would be acceptable.
Testing
1. Should I write my water and gas R2 readings on the test sheet or just on the back of the sheet?
2. I was told we should take all notes on the back of the test sheet but I'm concerned about losing time doing this.
I know I will be doing the R1+Rn & R1+R2 table for the ring final to write down all figures, and I will write down my RCD trip times, Ze, PFC etc.
But do I need to calculate my expected R1+R2 figures using the Resistivity of the cable size x cable length and divided by 1000 to comapre them to measured figures?
I know this will tell me what I should be getting but as I said I'm concerned with losing too much time.
Also, if my R1+R2 figure at each socket are more than 0.05 ohms +/- would I be expected to fix this or is it fine to leave if it isn't overly high? (I know the spur will be higher)
3. I'm pretty sure Im ok with this but I just wanted confirmation. After I do my r1, r2 & rn readings for the ring final, if I add togetehr say, r1 and r2 and divide by 4 then that will be my expected R1+R2 reading right?
4. for the heating system I know I need to do the R1+R2 test up to the FCU to record on the test sheet, but I need to check continuity at all relevant points after the FCU.
And what would be the best way to do that; wago the cpc and line together in the wiring box/JB and test at each point like normal?
I.R tests
I'm worried about not disconnecting all things that are vulnerable to damage when testing. I plan to do the following:
* disconnect light
* Replace ring final RCBO with 32A MCB. If 32A MCB is not available is any size ok as its only a low current passing through so for testing purposes it could be even a 6A right? Or would they not accept this.
* Remove carbon monoxide detector
* ensure Isolator for TP+N socket is on
What I'm unure about is:
* When a FCU/SFCU has a neon, can I just disconect the flyleads and should I just put them in a wago?
* If the heating circuit is not on a switched spur can I just remove the fuse before testing?
* I know I need to do the Cu to the DOL and then the DOL to the motor but will leaving the conductrs connected damage the DOL. Should I disconect and wago, and If i do can i not just connect the incoming cables to the outgoing cables of the DOL and not have to do a second I.R test?
* When doing the lighting, I'm getting confused how many times to operate the switches to cover all combinations. There's a feed to the first two way, then intermediate and then a 2 way and then upto the light, can anybody shed some light into the process of this.
Any input is appreciated.
Thanks,
George
This is my first post, although I have been browsing the forums for a little while now.
I work in BMS and have my AM2 on friday. The nature of my work means I don't get to test so there are a few things I'm unsure of and was hoping for some clarification.
I know for some people they may be obvious but I don't want to make any small mistakes and I want to be as prepared as I can be.
I know its a lot of questions but I'd be grateful with whatever people can clear up, specifically on the I.R tests.
General
1. Does the banjo bolt at the cu go inside and face out of the cu
2. does the SY between the DOL and motor only need to be banjo'd at one end as its for interference and not earthing?
Testing Sheet
1. would the AM2 bay be best classed as industrial or commercial so I know how long to put the next inspection due in part.
2. When I measure Ze I know to put the figure down as Zs at DB but on the installation certificate can i put this down too, as its so close to the main incoming supply it would be acceptable.
Testing
1. Should I write my water and gas R2 readings on the test sheet or just on the back of the sheet?
2. I was told we should take all notes on the back of the test sheet but I'm concerned about losing time doing this.
I know I will be doing the R1+Rn & R1+R2 table for the ring final to write down all figures, and I will write down my RCD trip times, Ze, PFC etc.
But do I need to calculate my expected R1+R2 figures using the Resistivity of the cable size x cable length and divided by 1000 to comapre them to measured figures?
I know this will tell me what I should be getting but as I said I'm concerned with losing too much time.
Also, if my R1+R2 figure at each socket are more than 0.05 ohms +/- would I be expected to fix this or is it fine to leave if it isn't overly high? (I know the spur will be higher)
3. I'm pretty sure Im ok with this but I just wanted confirmation. After I do my r1, r2 & rn readings for the ring final, if I add togetehr say, r1 and r2 and divide by 4 then that will be my expected R1+R2 reading right?
4. for the heating system I know I need to do the R1+R2 test up to the FCU to record on the test sheet, but I need to check continuity at all relevant points after the FCU.
And what would be the best way to do that; wago the cpc and line together in the wiring box/JB and test at each point like normal?
I.R tests
I'm worried about not disconnecting all things that are vulnerable to damage when testing. I plan to do the following:
* disconnect light
* Replace ring final RCBO with 32A MCB. If 32A MCB is not available is any size ok as its only a low current passing through so for testing purposes it could be even a 6A right? Or would they not accept this.
* Remove carbon monoxide detector
* ensure Isolator for TP+N socket is on
What I'm unure about is:
* When a FCU/SFCU has a neon, can I just disconect the flyleads and should I just put them in a wago?
* If the heating circuit is not on a switched spur can I just remove the fuse before testing?
* I know I need to do the Cu to the DOL and then the DOL to the motor but will leaving the conductrs connected damage the DOL. Should I disconect and wago, and If i do can i not just connect the incoming cables to the outgoing cables of the DOL and not have to do a second I.R test?
* When doing the lighting, I'm getting confused how many times to operate the switches to cover all combinations. There's a feed to the first two way, then intermediate and then a 2 way and then upto the light, can anybody shed some light into the process of this.
Any input is appreciated.
Thanks,
George
