Code Change Summary: Requirements have changed for mobile home, under-chassis wiring exposed to weather.

This section of the code has seen revisions for the last three code cycles. For such a small section, it would seem that it should have been easier than this. One thing to keep in mind is that the code panels are not “code writers”. The code panels vote to accept or deny a code change proposal (public input) based on the substantiation provided. It is up to the one submitting the public input to follow the NEC^® style manual in order to align the proposed code language with the way that the NEC^® is written.

In the 2014 NEC^® “Where outdoor or under-chassis line-voltage (120 volts, nominal, or higher) wiring is exposed to moisture or physical damage, it shall be protected by a conduit or raceway approved for use in wet locations or where subject to physical damage”.

The last part of the code section above in bold makes no sense at all.

In the 2017 NEC^®, a conduit or raceway used under the mobile home to protect wiring exposed to weather must be “identified” for use in wet locations rather than “approved” for use in wet locations. This rules out the idea that an inspector could approve a garden hose as a conduit to protect the exposed wiring. As well, item 2 now clears up the previous wording that made no sense at all. If the wiring is exposed to physical damage, it shall be protected by a raceway, conduit, or other means.

Below is a preview of the NEC^®. See the actual NEC^® text at NFPA.ORG for the complete code section. Once there, click on their link to free access to the 2017 NEC^® edition of NFPA 70.