[RE-wrenches] 208 V 240 in residential applications

[Peter Parrish]

It depends on the appliance. Some pure resistance heating units will work
okay but with a lower thermal output.  Other appliances will work if there
are internal jumpers that can be reset for 208V operation or terminal blocks
that can be  rewired for 208V. This is especially true for appliances that
have an internal transformer. Other appliances just won’t work at all. 

Peter T. Parrish, California Solar Engineering 
Ph. (323) 839-6108, Fax. (323) 258-8827

From: re-wrenches-bounces at lists.re-wrenches.org
[mailto:re-wrenches-bounces at lists.re-wrenches.org] On Behalf Of Marco
Mangelsdorf
Sent: Sunday, February 09, 2014 12:27 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] 208 V 240 in residential applications

So is this 3-phase system up and running and providing power to single-phase
(120 to ground) circuits AND split-phase-requiring circuits (240 phase to
phase)?

I would think that there would be no problem with the single-phase circuits
(if there are any).  But what about those split-phase circuits getting that
lower voltage 208 volts not @ 180 degrees out of phase but 120 degrees?

Sounds like kind of a scary experiment
.

marco

Friends:

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.

Watts
4000
 
 
 
 
Volts
240
208
Amps
16.67
19.23
% Difference in amps
13.33%
 

I am fairly comfortable that this is not an issue, but would like some
confirmation.  Thanks in advance.

William