electrotuko
Member
Would Code allow running three (L1, L2, Neutral) THHN 90C rated #8 wires and one #10 as non-current carrying for GND in ½†metal flex conduit? Circuit breaker will be 50A; cable will carry up to 50Amps.
A conduit fill calculator wants to know about everything going into the conduit, whether it carries current or not, as jamming is a consideration, as is heat dissipation. I use one supplied by Southwire, and the only way you get three #8 THHN wires, plus a #10 ground into 1/2-inch flexible metal conduit, without exceeding a 40 percent fill limit, is if the #10 wire is bare copper. Three #8 THHN stranded {218 mils diameter} plus one bare #10 solid copper ground {101 mils diameter} gives a 37.89% fill in 1/2-inch flexible metal conduit.Can a none Current‐Carrying Conductors be discounted form the estimations done by using Conduit Fill tables?
For example, for 1/2" metal flex conduit max three 8 gauge wires are allowed. In a four wire system the GND wire is not carrying current, can be not counted, hence it is allowed to use three 8 gauge and one 10 gauge GND wire?
Not sure exactly what you mean by "crawl space", but my understanding is that breakers need to be readily accessible -- you should be able to walk up, reach out and touch them.... I was going to add in the crawl space a branch box: Siemens 8-Circuit 4-Space 125-Amp Main Lug Load Center ...
By the way, did the tables change when large appliances went from 3-blade plugs to 4-blade plugs? Way back when, there wouldn't have been anything in a range outlet, for instance, for a fourth wire to connect to, so it wasn't going to be in the cable with the two hots, right?
This is awkward, but...
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