This whole high voltage connection discussion got me searching, and I found Phoenix Contact makes a DIN rail mount terminal block that is 1000 v rated.  That would seem to make way more sense than using MC 4 connects in a J box, and would provide the access for voltage readings and torque check that William mentioned.  Has anybody tried them?

https://www.phoenixcontact.com/online/portal/us?1dmy&urile=wcm%3apath%3a/usen/web/main/products/subcategory_pages/Modular_terminal_blocks_for_photovoltaics_P-15-09/eb8c193d-6a2d-4349-8f89-2d523fd5b04f

Ray Walters
Remote Solar
303 505-8760

On 5/7/21 8:47 PM, William Miller wrote:

Friends:

Call me old fashioned, but I cannot get any confidence on the Wago connector.  It seems somewhat akin to the back-wire mechanism on a 15A receptacle.  This connection relies on a spring that is subject to reduction in force when it gets hot.  We have seen many of the back-wire receptacles heat up and get more resistive as heat increases, creating more heat, etc.

We have learned when connecting battery cables to inverters or batteries that the best connection does not have any washer or any intermediate object between one conductor and the other.

I know wire nuts are not ideal (pun intended) but I like my conductors to be in direct contact, or under a screw terminal where I can determine and reconfirm the pressure placed on the conductor.  It is also necessary to have control over the pressure applied to the connection, which is why there are listed torque specs.

Yesterday I was measuring the line voltage on an SB Series 22 inverter.  This unit uses the Wago terminal.  There was no way I could get a meter probe into the Wago to measure line voltage.  I had to take the cover off the electronics sections and measure voltage at the circuit board.  I much prefer a screw terminal I can adjust the torque and get a meter probe onto it.

William Miller

Miller Solar

17395 Oak Road, Atascadero, CA 93422

805-438-5600

www.millersolar.com <http://www.millersolar.com/>

CA Lic. 773985

*From:*RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org <mailto:re-wrenches-boun...@lists.re-wrenches.org>] *On Behalf Of *Dan Fink
*Sent:* Friday, May 7, 2021 4:01 PM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] Wago Connectors (221 series)

Jason; From the Wago 221 data sheet, it's listed to UL 486C, 600V, 30A, Use Group C (industrial) . I have a copy of UL486C, and voltage is just specified for dielectric testing. That standard specifies tests with AC, because it is easier (and cheaper) to generate and ramp up compared to DC, and DC test platforms are relatively rare.

So my interpretation of UL486C is that because of AC voltage peaks compared to RMS (Vpeak = Vrms x 1,414), a 1000VAC rated connector under UL486C would need to be tested to 1414VDC. Working that math backwards, a 600VAC rating would mean the DC dielectric rating would be equivalent to 424.33 VDC.

How that would apply to AHJs asking you questions, I do not know!

Dan Fink

Owner, Buckville Energy Consulting LLC

IREC Certified Instructor for PV and Small Wind Installation

NABCEP Certified PV System Inspector

d <mailto:dan.f...@greendustrialtraining.com>anbo...@gmail.com <mailto:anbo...@gmail.com>

970-672-4342


On Fri, May 7, 2021 at 3:43 PM Jason Szumlanski <ja...@floridasolardesigngroup.com <mailto:ja...@floridasolardesigngroup.com>> wrote:

    In another thread these connectors were discussed recently. There
    was a question regarding the suitability for DC circuits. I don't
    think we came up with any answers or consensus on that. I see the
    connectors are UL listed to the 486C standard. I can't determine
    whether that is applicable to AC and DC circuits. Does anyone know?

    I have only used these on AC circuits and they have been very
    effective. Now I'm curious whether they can be used on DC circuits
    up to 600 volts.

    While on the subject, I noticed they are UL 467 listed for
    grounding and bonding. That's helpful where you have EGC splices
    for conductors up to #10 AWG inside junction boxes.

    Jason Szumlanski

    Florida Solar Design Group


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