Hello,

I'm starting a project to hook-up a optional stand-by generator. I have all the wiring for the transfer switch, service panel & essential sub. I need to run about 25 feet of 6/3 from the transfer switch to an outside wall along with a 14/2 (A/C power to the battery charger) and two 18 wires for the start control circuit. I can run standard romex for the 6/3 and 14/2 and appropriate cable for the two-wire start (most likely a 6/8 conductor 18 cable).

I obviously need to bring this outside to the gen-set. My plan is to use a LB to 1 1/4 or 1/12 liquid-tight(LT) (max 6 feet). Straight LT connection from the PVC LB to the LT and then a 90 deg LT fitting to the generator.

How do I make the transition from inside to outside wiring? I'll be connecting the LB to PVC conduit to penetrate the wall and then go into a large junction box. Can I then splice the romex to the THWN I plan to run in the Liquid Tight in that junction box? I've seen some "pre-wire" kits that run the romex right out to the gen-set, I suppose this is allowed because the whole assembly is listed.

I'd like to hear some feedback about the right/safe way to do this.

Thanks

Your plan is fine, exactly the method most installations would be done.

I just did a 12KW genset, the interior line was about 20 feet, then about 5-6 foot on the exterior to the gen. I used flexible conduit inside and LT outside, simply coupled together using an LB, used no junction box and no splices, by pulling through the 3-#6, 1-#10 ground, and 2-#14 starting circuit THHN straight through 1" flex.

tkrussell thanks for the reply.

I'm seeing the straight pull of THHN as the better and possibly cheaper way to get this done. One question the inside conduit, you used ENT? (Smurf tube?) did you go that route because it's easier than Sch 40? I've never used ENT and it's not required in my area (Northern NJ). I've read through Carlon's site and the snap connectors are an easier alterenative to glue. I'd be pulling the 2 #14's as the AC supply to the battery charger & carb heater, I'd pull two more #18 for the start circuit (30VDC ~ 2AMP). 1 Inch should have the proper fill capacity, now I just need to find it.

I used metal flexible conduit and metal liquidtite, and connectors for each. This material is not available at home centers, only at electrical supply houses.

I used a rigid coupling and a 6" steel GRC nipple into the LB ,transitioning at the point leaving the basement.

ENT and nonmetallic LT is fine also, just be sure to include a #10 green for the ground.

Ok,

Can I ask you to double-check me again?

I went to the electric supply to purchase some flexible metal conduit. Price and ease of install along with the guy working the counter drove me to LFNC-B, the functional equivalent for flexible PVC?

So it's cheaper, easier to install (for me) etc..

So the new plan LFNC-B about 27' from ATS to inside LB, standard PVC fittings no LT fittings inside.

LB inside to outside LB via PVC conduit. LB outside to LFNC-B again this time with LT fittings.

The LFNC-B is 1 1/4 so my fills are OK based on what I'm pulling 3-#6(H,H,N from gen), 2-#10(G for gen and new outlet in gen housing),2-#12(H,N for new outlet) & 2-#14(start control).

My #3 & #12 are de-rated to 80% because of > 3 cc counductors.

So would any sparky or AHJ get a chuckle from the LFNC-B inside instead of Sch 40? the are I needed to run through would have made Sch 40 prohibative (existing runs, plumbing, etc... It's bought, installed (not glued yet) and ready to pull wire...

Only problem is with the inside connectors, you probably have Sch40PVC fittings, and these are not rated for LNMC. They will probably work OK, but an inspector may fail the installation. Any electrical part is listed for their specific use, a good inspector will catch this.

Support the flex every 36" with straps for that size raceway.Any conduit support clip sized for 1-1/4' rigid or heavywall will work.

The conduit fill is fine, and when derating #12 THHN, start with 30 amps as the full ampacity and derate from there.