Ze & Pfc (Pefc & Pscc)

[Joshhosk]

I hope someone can help me as im getting different answers off different people

3P & N Supply

Ze:
Disconnect main earth
Set tester to 2 lead high L+PE (is this correct?) test between L1 - E / L2 - E / L3 - E recording the highest reading Ze (reconnect main earth)

Pfc (Pefc)
Set tester to 2 lead high L+PE (is this correct?) test between L1 - E / L2 - E / L3 - E

Pfc (Pscc)
Set tester to 2 lead high L+L/L+N (is this correct?) test between L1 - N / L2 - N / L3 - N

taking the highest reading of pefc and pscc and X2 (normally is L+L)

In what circumstances do you use 2 lead low / 2 lead high / 3 lead low?

can someone please guide me on this

 

[Deleted member 105166]

I have a metrel Mft but I believe on the AM2 it’s a megger mft

Can you not take your own MFT along for the AM2, so long as the calibration is up to date?
Otherwise it's rather like taking your driving test in a car you've not driven before.

 

[JamesL2022]

Legend mate!! Yeah I’m little nervous but I think I’ve prepared enough to have a good crack at it. I’m just nervous about live testing. I am assuming the supply to the testing board will have a rcd so I’m going to ask him to ensure I select the right settings to avoid tripping the rcd (3 lead low) I have told we have to do pfc (pefc) + (pscc) and take the highest reading X2 but as it’s 3p&N the highest reading would normally be between L-L/L-N. I’m just trying to practise filling out test certificates as I would hate for that to be the reason I fail. Any other tips you can give would be appreciated a lot. Thanks for your help mate
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I have a metrel Mft but I believe on the AM2 it’s a megger mft

you’ve got it spot on there, you’ll probably find your pssc will be the highest reading of both pefc and pssc, then you’ll double it as you say and write it as your pfc on the test sheets.Remember to convert it from amps to KA depending on the meter you use. The meggar I used gave me something like 646a so my pfc was 1.29ka

also worth noting I got the choice between a meggar or a fluke.
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Can you not take your own MFT along for the AM2, so long as the calibration is up to date?
Otherwise it's rather like taking your driving test in a car you've not driven before.

At the test centre I sat mine we had to use the instruments provided. Weren’t allowed to bring our own, he gave the reason it’s possible to pre programme them or pre set them or something and you may gain an advantage. I think the whole point being you need to prove you can use any test meter and set it up as such. I don’t agree personally i think you should be able to take whatever you’re most comfortable with.

 

[Joshhosk]

Can you not take your own MFT along for the AM2, so long as the calibration is up to date?
Otherwise it's rather like taking your driving test in a car you've not driven before.

Not as far as I am aware mate nobody has mentioned it
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you’ve got it spot on there, you’ll probably find your pssc will be the highest reading of both pefc and pssc, then you’ll double it as you say and write it as your pfc on the test sheets.Remember to convert it from amps to KA depending on the meter you use. The meggar I used gave me something like 646a so my pfc was 1.29ka

also worth noting I got the choice between a meggar or a fluke.
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At the test centre I sat mine we had to use the instruments provided. Weren’t allowed to bring our own, he gave the reason it’s possible to pre programme them or pre set them or something and you may gain an advantage. I think the whole point being you need to prove you can use any test meter and set it up as such. I don’t agree personally i think you should be able to take whatever you’re most comfortable with.

I will go with megger as its all I’ve used. how did you find the s plan as I’ve never wired one?

 

[JamesL2022]

Not as far as I am aware mate nobody has mentioned it
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I will go with megger as its all I’ve used. how did you find the s plan as I’ve never wired one?

The heating system isn’t too bad, it looks daunting at first but if you can follow the wiring diagram you’ll be fine. I wired it in about an hour and ticked off each component one at a time with a white board marker pen over the poly pocket so I could see what I’d done. The spec tells you what kind of cables you need between the bits that aren’t already pre flexed. There’s a couple of flex’s to wire and the rest is just in singles. We had to crimp different sized ferrules onto the ends that push into the main connection box, it’s a big din rail connector which makes it nice and easy to terminate them with no awkward chewed screws to deal with, well except for the programmer and solar controller but there’s minimal to terminate in those.

 

[Joshhosk]

The heating system isn’t too bad, it looks daunting at first but if you can follow the wiring diagram you’ll be fine. I wired it in about an hour and ticked off each component one at a time with a white board marker pen over the poly pocket so I could see what I’d done. The spec tells you what kind of cables you need between the bits that aren’t already pre flexed. There’s a couple of flex’s to wire and the rest is just in singles. We had to crimp different sized ferrules onto the ends that push into the main connection box, it’s a big din rail connector which makes it nice and easy to terminate them with no awkward chewed screws to deal with, well except for the programmer and solar controller but there’s minimal to terminate in those.

Doesn’t sound to bad! Did you find yourself running out of time or did you have plenty remaining to go over and double check things?

 

[JamesL2022]

Doesn’t sound to bad! Did you find yourself running out of time or did you have plenty remaining to go over and double check things?

I had about 30 minutes left at the end of the install. I think as long as it’s wired to spec and it works they are quite lenient because some of the terminations and covers are horrendously chewed up. Id have liked more time on the testing just so I could have gone at my own slower pace and been able to check stuff. You have to know your max zs for your circuits or where to find it in the on site guide. They have 4 or so little boxes on the back of the test sheet for you to record your r1+rn / 4 values and the rcd max disconnection time for x1 and x5 I was really worried about the live testing like you but it was okay. He’ll tell you exactly what test he wants you to do and in the order he wants to see it.Ze is first so you’ll disconnect the main earth and he’ll say pefc next so prepare the board (which is a subtle hint to reconnect the main earth) then it’ll be pssc. Then zs which is of the ring final circuit all the others are calculated from measuring ze earlier I measured it at the furthest point which was the outside socket. Then it’s basically just an rcd test and remember to press the test button on the rcd at the end to complete the live testing. ?

 

[Joshhosk]

I had about 30 minutes left at the end of the install. I think as long as it’s wired to spec and it works they are quite lenient because some of the terminations and covers are horrendously chewed up. Id have liked more time on the testing just so I could have gone at my own slower pace and been able to check stuff. You have to know your max zs for your circuits or where to find it in the on site guide. They have 4 or so little boxes on the back of the test sheet for you to record your r1+rn / 4 values and the rcd max disconnection time for x1 and x5 I was really worried about the live testing like you but it was okay. He’ll tell you exactly what test he wants you to do and in the order he wants to see it.Ze is first so you’ll disconnect the main earth and he’ll say pefc next so prepare the board (which is a subtle hint to reconnect the main earth) then it’ll be pssc. Then zs which is of the ring final circuit all the others are calculated from measuring ze earlier I measured it at the furthest point which was the outside socket. Then it’s basically just an rcd test and remember to press the test button on the rcd at the end to complete the live testing. ?

Awesome advice cheers and max zs values of each circuits are determined by Ze + (R1+R2) though? I’m pretty sure the value in the regs is 100% and the onsite guide is 80%

 

[JamesL2022]

Awesome advice cheers and max zs values of each circuits are determined by Ze + (R1+R2) though? I’m pretty sure the value in the regs is 100% and the onsite guide is 80%

your welcome. Your zs values will be calculated like that but you need to get the max values like you say either from regs or OSG for the maximum column. They don’t mind which set of values you use. I chose the on-site guide as I find it easier to navigate.

 

[Joshhosk]

your welcome. Your zs values will be calculated like that but you need to get the max values like you say either from regs or OSG for the maximum column. They don’t mind which set of values you use. I chose the on-site guide as I find it easier to navigate.

Will let you know how I get on mate thanks for all your input, if I pass I’ll get you a beer ??

 

[Joshhosk]

your welcome. Your zs values will be calculated like that but you need to get the max values like you say either from regs or OSG for the maximum column. They don’t mind which set of values you use. I chose the on-site guide as I find it easier to navigate.

Did most of my install today just have to connect everything up I’ve already done sockets etc man i was such a nervous wreck all day?the diagram is the same in this center too, did you use the orange wagos for your neutral and earth in the switches

 

[JamesL2022]

Did most of my install today just have to connect everything up I’ve already done sockets etc man i was such a nervous wreck all day?the diagram is the same in this center too, did you use the orange wagos for your neutral and earth in the switches

I think I was shaking a bit when I started mine! I Definitely was when doing the safe isolation. I hate being watched.

Yes I did mate, both earths and neutrals together in wagos. You could you use the loop terminal on the switch for the neutrals if you wanted to but I always wago or connector block the neutrals as I don’t trust the loop terminal with more than 2 or three cores in it.

have you got 2 days left? Give or take?

 

[Joshhosk]

I think I was shaking a bit when I started mine! I Definitely was when doing the safe isolation. I hate being watched.

Yes I did mate, both earths and neutrals together in wagos. You could you use the loop terminal on the switch for the neutrals if you wanted to but I always wago or connector block the neutrals as I don’t trust the loop terminal with more than 2 or three cores in it.

have you got 2 days left? Give or take?

Yeah I finish Friday mate yeah I’ve had a pretty rough day I haven’t gone as quickly as i hoped . Which circuits did you have to do safe isolation on probably got 2 hours left on the install to be honest

 

[JamesL2022]

Before the fault finding I did a safe isolation of the lighting circuit l, the motor circuit and then the full board. Keep your chin up Josh you’re doing what I done and questioning everything and over thinking. Just keep going I’m sure your doing fine pal.

 

[Joshhosk]

Hi mate, i went into it at a decent speed and kept on watching the clock after 3 hours. I should of gone alot faster i was too busy making sure all cables have no exposed copper and looking good easy to test and i ran out of time on my build. proper gutted they let me sacrifice my dead testing and live testing in order to hopefully pass my build. Proper kick in the teeth but i know next time just to rag it all in. ive got fault finding and safe isolation and online exam tomorrow. cheers for all your help mate

 

[JamesL2022]

Ah never mind mate. I’d have been more inclined to sacrifice the fault finding if they’d let you, as that’s probably the least stressful section to resit if you needed to do resit anything, but the build is probably the biggest time consumer you’d want out the way. Good luck for the final day.