Revised simpler/cheaper/no conduit! EVSE + self-wiring plan:
-
Siemens 30A Versicharge EVSE, in rear-fed configuration, to be mounted on the outside wall of the house/garage
- 40A GFCI breaker at the box (Siemens recommends the use of a GFCI breaker whereas Leviton does not)
- 8/2 NM-B cable routed indoors stapled to the rafters, spliced at an interior LB junction box with a
Multi-Cable Connector to two 8 guage THHN/THWN-2 wires plus a 10 gauge ground
- Run said THWN-2 wires through a 3/4" hole drilled through the wall, entering directly into the back of the Siemens EVSE, following
Siemens' own "fed-from-behind, hard-wired installation" instructions (no outside junction box or conduit runs involved)
The 30A Siemens EVSE is $850 vs. $1,100 for the 40A Leviton unit on Amazon, 8-2 NM-B cable costs roughly $0.90/ft vs. $1.30/ft for 6-2 NM-B, and this proposed "fed-from-behind" installation method allowable with this Siemens unit seems to me to allow for elimination of all conduit… right?
wwhitney said:
QueenBee said:
For example say the NM-B goes through the wall into a disconnect, or a weather rated metal junction box, or if that junction box also has a receptacle in it, all mounted to the outside wall. Are these considered damp/wet and thus NM-B should not enter them?
No, that's OK, the interior of a proper weatherproof box is considered dry.
Hmm. Would the above mean that I could legitimately run 8-2 NM-B right into the back of the Siemens EVSE in my above, revised plan (without splicing to THHN/THWN-2 at an inside junction box)? That'd make life even easier! My sneaking suspicion is that because it's a rubber grommet involved here rather than a connection to sealed conduit I should stick to splicing indoors and running THWN-2 through the wall. Thoughts?
In diagram form:
#2 in the above, the "Fed from Behind entrance", corresponds to the grommet in the photographic lower left in the below image, through which I'd feed the THWN-2 (or NM-B? see above):