14 Mar 2014

In 1976, an Underwriters Laboratory (UL) ruling required that all new meter bases be “continuous rated for 200 Amps,” otherwise only 70% of the actual rating would be considered usable, (i.e., a 200 Amp meter base that was not “continuous rated” could only be used on a 160 Amp or smaller service). Inspectors can probably assume that a rectangular meter base is compatible with the system it is serving, unless a major change or a new panel has been installed.

Here’s a list of common electrical defects in mobile homes:

COMMON DEFECTS in Mobile Home Electrical Wiring

  • Caravan or trailer electrical panel not properly protected from weather or not rated for outdoor use, rusted, corroded, unsafe: fire and shock risks (photo at left)
  • Improper connection to site, service entry, support, clearance over roofs
  • Aluminum electrical wiring
  • Lots of do-it-yourself wiring, exposed splices, bad or no GFCI, lamp cord wiring
  • Access blocked: due to limited storage space access to panel often blocked
  • Abandoned fixtures or boxes left open to weather
  • Loose, falling fittings and lights and fixtures inside and out;

Electrical Supply Defects

  •  Electrical meter & disconnect separate from the home, with own grounding electrode; therefore the panel in the home must be wired like a sub panel (isolate ground and neutral in the panel) with a 4-wire conductor that separates ground and neutral.
  • Factory-installed electrical equipment will have the bonding screws removed (dryer, range). Same must be done with owner-installed equipment..

Electrical Service for Mobile Homes

  • Traditional: cord and plug method to main switch;
  • Service equipment must be in sight of and no more than 30 ft from the exterior wall of the home it serves;
  • Cord and plug limited to 50A, sometimes 40A
  • Permanent feeders: SEC adjacent to home or mounted in the home provided manufacturer installed; may enter underground via conduit; If overhead, look for 4 color coded conductors ; (Hot, Hot, Neutral, Ground);
  • Masthead must give 8ft vertical clearance from all points of all roofs over which conductors pass, 2 exceptions:
  • 3-foot electrical wire clearance over the home’s roof is ok if roof is 4 in 12 or more
  • 18″ ok if no more than 4′ of service drop conductors pass over the roof overhang and if terminate in a through-roof raceway

For additional information regarding mobile home common electrical defects and or general electrical repairs contact a qualified Los Angeles electrician at United Plumbing Heating Air & Electric.