Hi William,
That looks excellent. I recently purchased a 3rd party interlock for an
Eaton / Cutler Hammer box, and it does not work securely. Both breakers
could be switched on at the same time due to the looseness of the fit.
I would like to try one of yours, and be happy to pay you for it.
Thank you,
Drake
_Drake Chamberlin_
_Athens Electric LLC_
_Ohio Electrical Contractor's License 44810_
_NABCEP Certified PV Installation Professional_
---
On 2025-10-14 01:40, William Miller via RE-wrenches wrote:
Friends:
For many years I had committed to the Outback product line. The
decline of Outback forced me to branch out.
I just completed my first install of Fortress Envy inverters. Not long
ago I installed a Sol-Ark 12K in my shop. Both experiences were mostly
positive.
What is interesting is the Envy and Soul-ark inverters do not come with
BOS equipment.
Now, if you want a PV disconnect, you need to add one manufactured by a
third party. This can be accomplished with a 600 volt safety switch.
If you want AC disconnecting means or distribution, you need to provide
outboard equipment. This is easily provided with off-the-shelf circuit
breaker panels.
Since my second Radian install I have avoided putting AC breakers in
the GSLC because wiring them was beyond tedious. Instead I ran my AC
leads right through the GSLC and straight to one of two breaker panels:
A generator-fed panel and in inverter-fed panel. Therefore I am not
inconvenienced by lack of AC BOS with the new generation inverters.
There is one other function that is missing with the lack of BOS
cabinets: Bypass switching. I think it is imperative that bypass
capabilities be provided. Inverters can fail and occasionally need
service and a bypass makes these scenarios much easier to handle. As a
matter of policy I will not support a batter-inverter client if they do
not have a bypass.
The Fortress and Sol-Ark manuals recommend use of an outboard double
throw switch for bypass. These are expensive and bulky.
Over the years I have developed circuit breaker interlocks that can be
fitted in a standard breaker panel and take care of the bypassing
function cheaply and efficiently.
For a long time I have been meaning to write an article on the subject
of transfer switches and bypass options. I finally got around to it
and it can be found here [1]. I hope my efforts writing this might
provide some insight on the subject.
I think I have fine-tuned my interlock design to a final iteration, as
described in the article. If any of you are interested in trying out
my Universal Bypass Interlock I am willing to send one for you to try
at no cost. Contact me off list if you are interested.
Sincerely,
William Miller
Miller Solar
17395 Oak Road, Atascadero, CA 93422
805-438-5600
www.millersolar.com [2]
CA Lic. 773985
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Links:
------
[1]
https://millersolar.com/MillerSolar/practices/Technical_Procedures/Interlock/Interlock.html
[2] http://www.millersolar.com/
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