On Tuesday 22 February 2005 03:55 pm, Scott Fraser wrote:
> John,
>
> First off, my answers are based on wiring in US and there may be slight
> variations if you are not under the US NEC (National Electric Code)
>
> Yes you can do this providing you meet a number of conditions.
> Dryer outlets.  These outlets are many times two hots (230V) and a
> grounding conductor.
> The grounding conductor is an equipment grounding conductor and is not
> allowed to operate as a current carrying conductor.  It is for fault
> current only.
> If you have only three wires on your dryer outlet, you only have a
> grounding conductor there and this cannot be used.
>
> Other dryer outlets have four conductors, there are two types of four wire
> connections
> Connection type #1
> two hots (230V)
> a grounding conductor (discussed above, green in color)
> a grounded conductor, often called a neutral conductor and either white or
> gray in color and smaller gauge than the hots.

I've *never* seen the neutral wire be of a gauge different from the others...

> The grounded conductor (neutral) on a dryer outlet is allowed to be smaller
> gauge wire than the hot conductors based on the premise that the heating
> coils will use 230V and the neutral is provided so that 120V can be
> connected to things like digital displays, clocks, oven lamps.

Or the motor in a lot of cases.  In this house,  the dryer outlet is wired to 
two-gang breakers,  but in older houses that used fuses it was quite common 
to hear the complaint that "the dryer spins but won't heat",  meaning one of 
the fuses was blown but not the other one.

> In this case, the neutral conductor will not be of sufficient gauge to
> carry the 40amps that it will see if you have only one set of motors
> running.
>
> Connection Type #2
> two hots (230V)
> a grounding conductor (discussed above, green in color)
> a grounded conductor, (neutral conductor) and SAME gauge as the hots.
>
> Now if you connection type #2, we can get to work.
>
> Number of motors allowed.
> Your 40 amp circuit can only be loaded to a maximum of 32 amps on a
> continuous basis.  With two lines, each fully loaded to 32 amps you could
> run a maximum of five motors at one time.
>
> Distance.
> How far from the connection point for the motors is your entrance
> panel?  With heavy current draws that the motor startup currents will
> subject the line to, you need to make sure that you will not see more than
> 3% voltage drop on a heavily loaded line.

Where'd you get that percentage figure from?

> Hope that helps,
>
> Scott

Of course,  then you have people who mess with this stuff that *REALLY* don't 
know what the hell they're doing.  Like what I found when I looked into 
complaints from the family downstairs (stepson, his wife, and grandkids),  
where they were "getting shocked by the dryer".

The outlet at the drier and was wired correctly,  so I pulled the cover to the 
breaker box.  Where I found black and white (neutral!) connected to the two 
poles of the dual-gang breaker,  and red (hot2!) along with the grounding 
conductor tied to the ground block.

Idiots!







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