Scott,
I know the UL requirements:
1) UL LISTED wire, in most cases, shall be marked with the UL in a circle or
parenthesis (circles look like parenthesis on small diameter wire),
some kind of manufacturer's ID (file number, name, trade name, etc), and
the wire type. This is minimum. there could be more marking requirements,
depending on the type of wire or cable.
2) There are rare exceptions to Listed wire, when it is costly or immpossible
to mark, the cable spool is labeled with all info, and the application does
not critically require marking.
3) UL Recognized wiring (ie,AWM Style numbers) are, in most cases, not required
to be marked. This is because this wiring is component wiring (ie, part of a UL
LISTED product), and the labels on the spool are easily accesible to the end-
product UL inspector.
4) A notable exception to this rule is VW-1 rated AWM. When AWM is optionally
rated VW-1, the only way to verify its rating is by the marking on the wire.
Therefore, if the application requires VW-1 rated cable, the cable must be
marked.
5) Keep in mind that there are rare exceptions to each rule, to keep flexibility
in the Recognition and Listing system, and to attempt to keep manufacturing
costs down where possible, without compromising safety. These rare exceptions
have to be documented and examined on the end-product level.
Also, it is important to note that if you have used unmarked cable in an
end product when you should have used marked cable, as long as you can prove
that the cable is suitable for your application (either by documentation
from the manufacturer or through testing) you should NOT be required to rip it
out and put in marked cable. Only installations covered in the National
Electrical Code (NEC), which are mostly building-level installations,
will insist on ripping out existing wiring, if they are not marked correctly.
Wiring inside of UL-Listed products should NEVER be required to be replaced for
marking reasons only (As long as the wire is proven suitable for the
application).
I assume the other agencies, like CSA, VDE, etc. have similar policies.
Regards,
Bob Tims
Compliance Engineer
Ericsson Messaging Systems Inc.
