If I recall correctly, double insulation doesn't require two physical
separate insulators. You could use a single insulator that has twice
the rating! such as 600V rated wire.
Hans
______________________________ Reply Separator _________________________________
Subject: Double Insulated Wire information
Author: Non-HP-DOUGP ([email protected]) at HP-ColSprings,mimegw5
List-Post: [email protected]
Date: 10/27/97 11:01 AM
Hello all,
I have need for double insulated wire in sizes ranging from 22 - 4 AWG and
larger for up to 300Vac mains applications. Currently we often use 600V
rated heatshrink over 300V rated wire, labor costs are very high.
I have already checked into the "BN" style wire and found that the PVC core
insulation carries the full voltage rating of 600V and the nylon jacket is
only for solvent and abrasion resistance, i.e. the nylon jacket is not
voltage rated. It would be better if each layer contributed 300V for basic
and supplementary insulation.
We also use in certain cases UL rated silicon or EPDM wire and safety
compliance is achieved by virtue of the insulation thickness and impulse
ratings, not the voltage rating of the wire. This solution does not work
with IDC connectors as the insulation is quite thick.
We have also successfully used "triple-insulated" wire from Furukawa, but
this is only a replacement for magnet wire in transformers.
I have found a source for Silicon FEP over Teflon (Rowe Industries) which
makes for selective stripping. This works well for IDC connectors. But
their range of sizes is limited to 24 - 20 AWG.
Another possibility would be to extrude UL1015 PVC insulation over a UL1180
Teflon stock wire. The 180C at the core and 105C overlay makes for ease of
stripping as the 2 layers of insulation would not blend. I have not
received any quotes on this as yet.
I realize that a custom wire like this is not likely to be approved by any
agency but if the acceptance test procedures and construction information
are available then my inspector can review and certify the wire for the
application.
Anyone have ideas or sources?
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
Doug Powell
Compliance Engineer, [email protected]
Advanced Energy Industries, Inc.
www.advanced-energy.com
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
