Doug,
I agree with Peter. When I was at TUV I had investigated products along with
the UL Engineer who never had a problem with using an AC rated fuse to
protect a DC rated product, as long as it did it's job. However, when UL
sent another Engineer for a DC product investigation he required that the AC
fuse be replaced with one that had a DC rating. Obviously a major problem
for the company since UL has accepted this practice in the past.
I believe as long as the fuse is located within the product and protects the
product from any hazards as stated within the testing standard, it should be
acceptable.
Ed
From: [email protected]
Reply-To: [email protected]
To: [email protected], [email protected]
Subject: Re: Got a beef with an NRTL ...
Date: Thu, 19 Oct 2000 22:17:11 EDT
Doug,
I have used DC-DC power supply with the AC fuse on the PSU in our products
many times and have never heard such a saga from an agency. The PSU report
will certainly have C of A and in addition to that almost all test houses
when testing DC-Dc power supply which is fitted with AC fuse, they will
conduct certain abnormal tests to ensure that fuse does what it is supposed
to do and will list all the fuses that were used during the testing. In
fact
UL PAG 1950 has one particular clause about such thing and will allow the
PSU
manufacturer to use AC fuse on a DC-DC PSU provided certain conditions are
met.
I suggest you go back to the top management and demand that they show the
clause of the standard where it says this practice is not acceptable. If
you
look at most fuse catalogues, you will notice that many of the fuses even
though they are rated for AC, they have also been test for DC and fuse
manufacturers would confirm this.
Don't give up and demand full explanation. It seems to me that your product
certification engineer is either have not enough experience or he is after
promotion.
Thanks
Peter
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