Industrial wiring

I haven't looked it up in the 2014 code, but it used to be you could splice in an LB ( condulet) on strict guidelines. The first thing is the LB has to have a cubic inch value stamped on it somewhere. Then using the guidelines for box fill per conductor, you could splice if the cubic inch value of the LB was sufficient to handle the wires. If you have wire that requires 2.5 cubic inch per wire and you splice 2 wires in to 2 wires out, you would need an LB of 10 cubic inches or more. That's providing you don't have other wires in the LB that you aren't splicing. Typical places I have seen condulets used is for connecting small valves etc. that don't have junction boxes as part of the valve. Splicing large wires in an LB probably violates code for other reasons and is not good practice even if it were.

The only other comment I have and I just read this in a Residential Wiring manual, not the actual code, was an additional remark "where permitted" pertaining to splices in an LB.
If in doubt, check with your inspector.