When is UL certification necessary?

I'm having a hard time figuring out exactly when its necessary to enlist the
services of UL, when its might be a good idea, and when its just a waste of
money. They are, what, a QC lab? Do they test products to UL standards,
government standards, legal requirements, or what?

If I create a product, say a board that runs on 5V, and that 5V comes from a
UL listed wall transformer, does the product need testing? What if the power
comes from a USB port? What if you just plug the damn thing into the wall
and gets its power that way? Does it make a difference whether the product
is slated for sales into industrial, commercial or consumer applications? Is
there a repository of "UL Approved" circuits?

If you call UL on the phone -- in my experience -- they won't tell you
anything other than, "Send us the product and we'll take a look." Yah, take
a
look at my arse. They are a for-profit business.

Where does one start to look for safety and legal requirements for
embedded-type stuff (excluding RF and medical)? Do you just pluck your way
through the CFR and ASTM requirements?

In article <YKOwc.53359$mm1.12134@fed1read06>, Mike Turco wrote:

> I'm having a hard time figuring out exactly when its necessary
> to enlist the services of UL,

When your customers or your lawyers require UL approvals for
your products.

-- 
Grant Edwards                   grante             Yow!  This ASEXUAL
                                  at               PIG really BOILS
                               visi.com            my BLOOD... He's
                                                   so... so... URGENT!!

Mike Turco wrote:
> I'm having a hard time figuring out exactly when
> its necessary to enlist the services of UL, when
> its might be a good idea, and when its just a waste
> of money.

UL is an optional certification.  (Actually, I think their stance is
that they're not a certification, just a testing lab that checks for
appropriate compliance.  "We didn't say it was safe, just that it met
the applicable standards.")

It's not "required" officially, though many organizations may require it
(large companies, government, insurers, distributors).  It's also
expensive for a startup product.  (IIRC, $8K+ for safety + RF emissions
for US only)

UL tests your product to meet applicable regulations (e.g., safety, FCC,
etc.).  This varies by product type, intended application, and target
market.


> If I create a product, say a board that runs on 5V,
> and that 5V comes from a UL listed wall transformer,
> does the product need testing? What if the power
> comes from a USB port? What if you just plug the
> damn thing into the wall and gets its power that
> way? Does it make a difference whether the product
> is slated for sales into industrial, commercial or
> consumer applications?

Yes on all counts, and each of these points change the testing
requirements.

> If you call UL on the phone -- in my experience --
> they won't tell you anything other than, "Send us
> the product and we'll take a look."

IME, they can be very helpful, given the right questions / approach (see
below).

> Where does one start to look for safety and legal
> requirements for embedded-type stuff (excluding RF
> and medical)? Do you just pluck your way through
> the CFR and ASTM requirements?

I started by calling UL. :-)  Seriously.

I took the approach of:
* We need guidance before engaging UL services (i.e., we intend to use
UL for testing, but we're in the design phase right now; nothing can be
sent for review)
* To prevent a badly flawed design (and re-test fees), we need info on
the relevant certs (also so we know what certs are being covered for our
money)
* This is a first-time product, and no experience with certification
testing
* Here's what the product is / does / market / application
* Which UL certifications apply, and what regulatory requirements to
they satisfy?
* What will it cost, how long will it take, what's involved? (e.g., how
many units will be tested to destruction?)  What about additional
jurisdictions?

I've learned several things as a result:
* What it'll take to get UL, why I want it, and when I need it
* We want to avoid classification as an office computing device because
it triggers a load of mandatory expensive FCC tests.
* Our first product qualifies as a lab device, which is an exemption
category for FCC testing.
* Use a UL / FCC / CE wall wart whenever possible, instead of
integrating line power.

It took several discussions and e-mails to fully qualify our device's
categories, after which UL finalized what'd be involved.  Expect it to
take several days to get the details.

Good luck! (and what king of device are you creating?)

Mike Turco wrote:

> I'm having a hard time figuring out exactly when its necessary to enlist the
> services of UL, when its might be a good idea, and when its just a waste of
> money. They are, what, a QC lab? Do they test products to UL standards,
> government standards, legal requirements, or what?

It is necessary to get UL approval when you or the customer buys any 
kind of insurance.  For example, if you insure yourself against 
product liability or your customer insures themselves against 
hurting their employees or their customers (if they are an OEM).
If your product melts down on someone's lap, they can sue your
customer who then sues you.

Ask your customers the question. - RM

On Sun, 06 Jun 2004 21:36:43 -0700, Richard wrote:
> Mike Turco wrote:
>> I'm having a hard time figuring out exactly when
>> its necessary to enlist the services of UL, when
>> its might be a good idea, and when its just a waste
>> of money.
> 
> UL is an optional certification.  (Actually, I think their stance is
> that they're not a certification, just a testing lab that checks for
> appropriate compliance.  "We didn't say it was safe, just that it met
> the applicable standards.")
> 
> It's not "required" officially, though many organizations may require it
> (large companies, government, insurers, distributors).  It's also
> expensive for a startup product.  (IIRC, $8K+ for safety + RF emissions
> for US only)
> 
> UL tests your product to meet applicable regulations (e.g., safety, FCC,
> etc.).  This varies by product type, intended application, and target
> market.

You should probably plan/budget for a couple of trips, esp. if you
haven't done it before and if you're trying for (something like) FCC Class
B rating of (significant) computing gear. I took some gear from a
subcontractor design shop (with their own Faraday cage test room, where
they did pre-testing) to UL in Chicago for testing. We had a number of
surprises: e.g. row of LEDs showing through a slot in the case: yep, wave
guide/antenna, beaming out all kinds of harmonics of the internal clocks.
This was a graphics computer about 10 years ago. Devices and designs are
probably a lot better now, but keep in mind that every bit of wire is an
antenna! Every cutout/gap is a wave guide. ...and so on...

In their case, I think the client wanted the Class B mostly for "bragging
rights" (and part of their marketing spiel?) because the actual
installations were going to be industrial (cable TV head ends). We met
Class A. However, it is true that TV people are sensitive about EMI, etc.

BTW, I think the FCC stance is that if any gear causes excessive
interference (above the FCC Class ratings, and someone complains), it is
the operator's responsibility to remove/fix it. If you can show UL
testing passed FCC compliance, you have a "get out of jail free card",
and they'll likely look at other gear first. However, if your "sample"
passed FCC tests, but your production is defective, you might still have a
problem. If any of your customers incur extra costs like that, they
might try to sue you, for supplying defective/deficient gear. Even if you
have weasel words in your contracts, they might try "best practices" ploy.

-- 
Juhan Leemet
Logicognosis, Inc.