Letters

摘要

I just picked up and read your July 2018 issue (FHB #276). It's a great issue, jam-packed with great topics. In reading the subpanel install article by CJ Nielsen, I found I love his methodical and neat approach-it really shows his dedication to the craft and his pride in his workmanship.One of his steps raises a question for me, though. I noticed he zip-ties the wires together along each side inside the panel. Does this method pose any sort of a fire hazard? As current flows through the wires, the wires heat. Because they're kept together, air cannot flow across each wire and reduce the heat buildup. I know conduit contains limitations on the size and number of wires you can place in them to prevent overheating. Are there any similar limitations on wires not contained in a pipe?I would prefer to use the author's neat method, but want to make sure I do not have any problems down the road. Thanks and keep up the great work.CJ Nielsen replies: In 15 years of installing zip ties inside a load center, we have yet to encounter a problem with the inspector. Using zip ties in an electrical panel is not only a very common practice, but you could argue that in some cases it's actually required by code. For instance, in order to identify circuits in conduit containing any shared neutrals, section 210.4 of the National Electrical Code requires circuits to be grouped together in order to clearly identify each neutral to its corresponding circuit.