Wire Voltage Rating

We recently caught a purchasing error in production. 300V wire was
accidently purchased instead of the specified 600V rated wire. This
wire is used to connect a 3 phase 480V motor to a combination starter.

After this occurred I tried to figure worst case scenario but am having
trouble. If a single line voltage is 277 to neutral, is the 300 volt
wire okay in this case?

If line to line is 480V, wouldn't two 300V wires really be 600V
protection from conductor to insulator (for line 1) to insulator to
conductor (for line 2)?

 

277v is bit close for comfort isnt it, what is the maximum the line to earth
can go to under fualt conditions ?
ie floating nuetral, short from line to nuetral and or line not conected to
source etc?

I'm not familiar with practice regard to specifiying cable voltage ratings
with regard to safety factor/derating for curent/temp/being enclosed etc.

so I wouldnt be very happy to sign the aceptance.

Colin =^.^=

 

This line of inquiry may be beside the point.

What material does your UL file's constructional data sheet state is
to be used?

Similar UL wire styles with differing voltage listings differ usually
in one significant physical feature - the thickness of the insulation
layer. It may be acceptable to sleeve the erroneous material to meet
constructional data statement wording - check with your liason officer
for the file in question.

This won't save you any money, but might allow deadlines to be met.

RL

 

277 volts is the RMS line voltage not the Peak which is 277 x 1.414 =
391, so your 300volt insulation is not satisfactory for one line to
ground under good conditions.

Sack the specifier and buy the correct wire, is the only good advice.

 

Nah, don't sack him - do the fix, and take the cost out of his
paycheck. >;->

Cheers!
Rich

 

Oh, my! I thought 600V wire was required for 120V service. It seems
someone unloaded stuff they couldn't sell. Well, just hook two wires in
series. ;-)

 

I spoke to a UL person today. He told me 300V and 600V wire are tested
the same if it has the AWM (Appliance Wire Manufacture - i believe)
mark. Both are subjected to a 2000V dielectric test!

 

Is the UL person OKing the substitution?

RL

 

NO.
If it is labelled 300 volts then thats the evidence that will be used
against You when there is a fatality.

 

If there's any accident insurance & criminal justice will likely look at the
rateing. Not that the cable happends to be the same as the 600V version.

Useing it is like playing poker..

 

and thats really the only way to look at it.

Cheers
Terry