14 Mar 2014

An isolation switch, also referred to in many sources as a “transfer switch” is a double-throw switch that changes electrical connections between two alternate sources. This is an “exclusive OR” switch that flips the panel power feed between the two sources but never allows both to be “on” or “connected” to the sub panel simultaneously. A local electrician in Los Angeles at United Plumbing Heating Air & Electric encourages this design because it prevents simultaneous electrical power feed from two sources.  You’ll see that each individual electrical circuit is switched between “Generator”, “Off”, and “Line” voltage.

An isolation switch allows only one electrical power source to be connected to feed a sub panel at a given time. This avoids, for example, the hazard of shocking electrical workers who might be repairing the main electrical service.

As an example of an isolation switch set-up for an auxiliary electrical power generator hookup at a private home.  A backup generator hookup will provide limited electrical power for critical building circuits during a power outage from the electrical utility.

A properly and safely wired & installed backup or standby electrical generator with sufficient wattage output and fuel storage to power a typical residential home for several days in an emergency costs “well over $10,000, though with some care for safety one can power a few critical electrical circuits in a home (heat, refrigerator, a lighting circuit) using a less costly contractor-grade portable electrical generator as well.

Factors driving up the cost of an installed backup electrical generator for the home include

  • Backup Generator: cost of the electrical generator itself, size varying according to the number and ampacity of electrical circuits to be supported in the building; typically a portable or stationary generator suitable for home backup power use provides 5,000 to 7,000 watts of power.
  • Portable Electrical Generator – $400. – $2000. [3000 – 90000 Watts capacity]
  • Stationary Generator: $4500. – $8000. & up [5000 – 20,000 Watts capacity]

Backup Generator Electrics: The cost of the transfer or isolation switch system itself can vary significantly depending on whether you expect to be present to turn on the backup or standby generator.

For additional information regarding back-up generators, transfer switches, or general electrical inquiries call a local licensed electrician in Los Angeles at United Plumbing Heating Air & Electric.