IR testing

[SparkyMarky]

Just completed my first install, have assessment on Wednesday, oh joy. Have a bit of a mental block concerning ir testing of DC cables to array frame, my course notes say "join the +ve and -ve cables of the array together and test to the array frame". At this stage of the game if I join those cables then I'll have Isc flowing round the cicuit and won't my tester get upset? Also, can you push 500v test voltage through a PV module?

 

[lilman]

Page 53 Dti guide.

 

[steptoe]

erm, NO

dont be pushing volts like that through, although you may well find your ARRAY is actually pushing 600V out of it depending on number of panels,

what is your assessement for? MCS?

 

[kme]

Welllllll.

1. You need to measure Isc of the string anyway. How are you currently doing that?

2. If the test is between the frame and the DC output, you could measure one of `em then the other - ANY reading is an issue, TBH. you aren`t putting the voltage between the string; as Albert says, you`re likely to have 500VDC+ coming down those cables anyway!!!!!

3. r.e.joining +ve and -ve. I`d STRONGLY advise using your DC isolator as the shorting switch.

KME

 

[wozz]

Forgive me if im wrong im not actually MCS or ever done a install, but surely this is meant to be carried out on the ground and tested to the panel frame. Does it also have to be tested once up on the roof?

 

[SparkyMarky]

Thank you all, have now read page 53 and it's all become clear! My understanding Wozz is that you do an IR test to the frame when it's on the roof to check that you haven't squished any cables. Yes, assessment for MCS, I'm currently wading through the paperwork.

 

[kme]

Wozzer:

You check each panel for output voltage - within spec, allowing for light conditions.

However, to test the ARRAY; you`d have to connect all the panels together - that`s going to be a PITA!!!.

So, once they`re on the roof, and the DC array cables are to the isolator, you can provide array voltage (Voc) and current (Isc) with a given Watts per square Metre of light on the array.

there wouldn`t be a point doing the insulation test between the array frame on the roof, and the panels on the ground.........