[SML] minor rant

e-mail frank.wood95 frank.wood95 at ntlworld.com
Sat Feb 14 19:11:15 UTC 2015


You sometimes find odd colours in equipment wiring. I remember a piece
of German gear we had just had delivered. The three-conductor power
cord had red, black, and white cores. Believe it or not, the RED core
was earth, as we found out the hard way.

I also recall the power supply for a 2KW HMI luminaire, which came in
to my workshop for repeatedly blowing fuses. The internal wiring was
in light red and pale brown. A previous attempt at repair had confused
the two, and resulted, at a late stage in the 'strike' sequence, in
putting a full short on the incoming supply. This took out the 15A
fuse in the power supply, left four BS1362 13A fuses unscathed (we
were in a temporary workshop, with multiple 4-way splitters around),
took out the 40A breaker for the workshop and the 60A breaker behind
that, bringing the whole block to a grinding halt.

Circuit protection needs more thought than many people think.

On 14 February 2015 at 13:13, Dan Sheehan via Stagecraft
<stagecraft at theatrical.net> wrote:
> just thought I'd share:
>
> 240 V power is commonly black and red for the two hot legs
> (white is reserved for neutral)
>
> Baseboard heater presents two wires:  red and black.
>
> Mount-in-unit thermostat for same,
> made by the same mfg and purchased in the same ubiquitous store,
> has two pairs of red & black wires.
>
> So, connect one red/black pair to the red/black L1-L2 source,
> other red/black pair to the heater red/black, right ?
>
> - - - -
>
> No, WRONG !
> That configuration is what circuit breakers are for!
>
> T-stat uses 2 reds for line, 2 blacks for load.
> Not marked on the unit.
>
> ( I checked after (my bad!) installing first of two units,
>  before attempting to apply power)
> --
> ...Dan Sheehan
> Fixer of things that break
>
> ____________________________________________________________
> For list information see <http://stagecraft.theprices.net/>
> Stagecraft mailing list
> Stagecraft at theatrical.net
> http://theatrical.net/mailman/listinfo/stagecraft_theatrical.net



-- 
Frank Wood




More information about the Stagecraft mailing list