[RE-wrenches] HV Module Testing

Thu Apr 11 06:39:24 EDT 2019

Voc is 37.1
That times 1.25 is 46.38 V

It is less than 120 V, so I guess I can not test individual modules on
the 500 V setting. Is that the case? 

Thanks,

Drake 

----- Original Message -----
From:
 "RE-wrenches" <re-wrenches at lists.re-wrenches.org>

To:
"RE-wrenches" <re-wrenches at lists.re-wrenches.org>
Cc:

Sent:
Wed, 10 Apr 2019 15:51:42 -0700
Subject:
Re: [RE-wrenches] HV Module Testing

The IEC 62446 standard for IRT on PV is:

Voc at STC x 1.25 = 120 V to  ≤ 500 V, test to 500 V
Voc at STC x 1.25 = > 500 V, test to 1,000 V

They specify using one of two methods: 

1. With the array short circuited (a la the Seaward test meter style)

2. Testing both positive and negative to ground - both the negative
and positive leads need to be isolated (fuse open/breaker off, and
disconnected from parallel busbar connections).  In my experience,
putting the meter in series (meter positive to PV negative, meter
negative to ground) is usually sufficient for finding ground-faults.

Make sure the meter-to-ground connection is low resistance, and that
the connection point is something that is actually bonded to the
equipment grounding system. 

Temperature, humidity, and the amount of "glass" being tested will
have significant impacts on measured results, but you're really
looking for an outlier, assuming it isn't a hard fault that could've
been found with a DMM or a visual inspection.

Always a good idea to check with the module manufacturer to see if
they have documentation on their recommended procedure.

Cheers,

Brian Mehalic 
NABCEP Certified Solar PV Installation Professional™ R031508-59
National Electrical Code® CMP-4 Member
(520) 204-6639

Solar Energy International
http://www.solarenergy.org [1]

SEI Professional Services
http://www.s
eisolarpros.com [2]

On Wed, Apr 10, 2019 at 3:07 PM <drake.chamberlin at redwoodalliance.org
[3]> wrote:

That is very helpful. If I do the high voltage test, can I test from
both positive to the frame and negative to the frame? 

Thanks,

Drake 

----- Original Message -----
From:
 "RE-wrenches" <re-wrenches at lists.re-wrenches.org [4]>

To:
"RE-wrenches" <re-wrenches at lists.re-wrenches.org [5]>
Cc:

Sent:
Wed, 10 Apr 2019 10:35:50 -0700
Subject:
Re: [RE-wrenches] HV Module Testing

Drake
I have performed test for manufactures and you must keep the test
voltage under the max rated voltage of the module, we have a bunch of
tests we do but in short, you need to see the modules up close, look
at the edges and back sheets look for green, brown or black spots, you
need to do testing both dry first then wet if it is a ground fault
concern. Most of the time the visual will find the issues but you
still want to verify what you think you see. Make sure you look at the
wiring to and from, the combiner box(s) or even the inverter(s).

On Wed, Apr 10, 2019 at 8:31 AM Drake
<drake.chamberlin at redwoodalliance.org [6]> wrote:

  Hello Wrenches, 

 We are troubleshooting an array of Orion modules, either 230s or
250s. The array is showing a ground fault. 

 We would like to test these modules with an insulation tester? 

 We would like to apply 500 V or 1000 V to each the + and – and test
resistance to ground. 

 Is this practice safe for individual PV modules? Is there anything I
should be aware of before attempting this?

 Thanks,

 Drake

Drake Chamberlin
Athens Electric LLC
 OH License 44810
 CO License 3773
 NABCEP Certified Solar PV 
 740-448-7328
http://athens-electric.com/ [7] 

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