[RE-wrenches] meggering module-level electronics

[Nick Soleil]

Hi Kirk,

There is little to no need to megger test Enphase cabling, and we would not
recommend it as part of the normal installation process.  Since the
microinverters are connected to the cabling in parallel, a microinverter or
module failure will not impact the other microinverters/modules on the
branch circuit, so it is pretty easy to find where a problem has occurred.
If a fault occurs on the DC wiring of the microinverter/module pair, then
only that one microinverter will be affected.

If you want to perform an insulation resistance test on an Enphase array,
you must ensure that the microinverters are unplugged from the Engage
cabling.  The surge suppression hardware within the Enphase microinverters
will provide a false positive reading if you try to megger test the cabling
with the microinverters attached to the cabling.

On Mon, Jul 20, 2015 at 2:13 PM, Kirk Herander <kirk at vtsolar.com> wrote:

> I recently had to megger (IRT) a Solaredge array to debug an inverter
> failure.  I didn’t think it possible, but a SE tech told me how to do it
> without frying the optimizers. I had to float, then short both pos/neg
> string leads and then megger this connection to ground. I’m not sure if it
> meggered all the way through to the panels or just through the optimizer
> series output. I assume the module input is isolated under this condition.
> Anyone have experience IRT’ing Solaredge or other (Enphase, Tigo, etc.)
> mod-level electronics? Thanks.
>
>
>
> *Kirk Herander*
>
> *VT Solar, LLC *
>
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-- 

Cordially,

Nick Soleil
*Enphase Energy* | Field Applications Engineer

office 707-763-4784 <%28707%29%20763.%204784> x7267
cell 07-321-2937

<http://enphase.com/>

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<nsoleil at enphaseenergy.com>

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