[RE-wrenches] 208 V 240 in residential applications

William Korthof wkorthof at gmail.com
Mon Feb 10 07:51:00 PST 2014


Every residential electric ranges I've ever checked is dual-marked for 208V and 240V. At 208 volt supply, the resistive elements pull fewer amps, so with lower amps and volts, you get noticeably less output power (takes and extra minute to boil a pot of water). But everything still works.

While single family homes are almost always supplied by 120/240 split phase, there are millions of Multi-family residential homes (condos and apartments) in the country, and the majority are supplied with 208v three phase power, with each individual unit getting 2 of three phases plus the neutral. 

Even electric water heaters and most AC compressors that I've checked also seem to be dual rated (208/240V). Electric car chargers are also agnostic. 



/wk

William Korthof
714.875.3576
Sustainable Solutions
#956904

> I feel sort of stupid asking this, but it has never come up for me before:
> 
> 
> 
> I have inherited an off-grid install gone-wrong.  The system is 208 three
> phase with Sunny Boys and Sunny Islands on a mini grid.  It was designed as
> three phase.  I presume this was to increase capability with stacked SMA
> inverters.
> 
> 
> 
> Will the household appliances (small cooktop, booster pump, well pump) run
> as well on 208 as 240?
> 
> I always do my research before wasting all of your time.  The web
> delivered a lot of "forums" wherein opinions were expressed, but little
> hard data from bona fide professionals.  I also did some calculations, see
> below.  I downloaded a manual from a random electric range and saw it was
> specified as 240 or 208.
> 



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