In article ,
"Wild Bill" wrote:

The UL symbol on electrical devices isn't an all-purpose designation. Many
UL listed devices are listed/specification specific to be acceptable for a
single purpose.

Consumers buying products labeled on the packaging as "surge protectors"
were purchasing devices that were UL listed as interconnecting devices.

I believe the UL listed symbol used to represent a level of safety and
quality/reliability, when there weren't so many thousands of different
electrical devices, for so many specific uses.
Examining some of the low quality imported home and commercial lighting
products, for example, which have UL labeling, makes me doubt that the UL
symbol is a reliable overall representation of quality.
The products in the stores may not be of the same quality as the design
specifications that were submitted for approval (very poor quality control
at the manufacturing level).

There are numerous other international organizations that approve electrical
component designs.
When I see several international approval symbols on a product, I feel
confident that the product is very likely to be reliable.

Yes. All that UL and DIN and CA and the like care about is safety, so
their tests verify only that the device won't catch fire or electrocute
anyone. They do not test if the device is of good quality, or suited
for its claimed purpose. Only safety is tested.

That said, a product with multiple symbols usually comes from a large
company, simply because it costs lots of money to go through all those
tests, and larger companies usually finish the engineering before
shipping the product. But not always.


This gets into an area where the user needs to know what any type of
approval labeling is actually intended to represent.

We've all heard mil-spec thrown around casually. There are specifications
for all types of products, and without actually knowing what the specific
designation actually represents, any particular product may not be suitable
for it's (next) intended use.

When someone has a mil-spec ratcheting tie-down, they might not know if the
original specification was to tie down aircraft or what other use it was
spec'd for.

All MIL-SPECs are now available on the internet, so a little googling
should tell the tale. If the product claims to be MIL-SPEC, but doesn't
give the spec number, ignore the claim and don't buy the product.


For wire, one should know the insulation breakdown voltage rating and the
acceptable limits of the insulation, as an example.

The National Electrical Code and UL require that this information be
stamped on the wire itself, and verified by certain UL tests. It isn't
just a manufacturer claim.

Joe Gwinn