I'm not familiar with UL 1459, so I'll not address that issue.
The idea of using a PCB conductor as an overcurrent-protection element
is without merit. (Bluntly: it's really a dumb idea.) A fuse is a
device crafted to meet very specific requirements. Its clearing
characteristics are entirely predictable within specified tolerances.
On the other hand, the cross-sectional dimensions of etched copper
probably vary from board to board, but certainly between lots. Copper
also has a large temperature coefficient that will also affect its
fusing characteristic.
One of the unanticipated expenses that manufacturers run into when
they try to skim on the cost of adequate and responsible safety
measures is the cost of legal fees and settlement monies at litigation
time. Corollary: It really costs less to do it right. Sooner or
later, someone may get hurt using your product. If the product is
designed properly and safely, it's a whole lot easier to demonstrate
that the user was operating the device in an unsafe manner.
PAG
______________________________ Reply Separator _________________________________
Subject: Safety
Author: [email protected] at Internet
List-Post: [email protected]
Date: 7/29/96 08:38
Hi TREG -
We have the "opportunity" to purchase a cheaper transformer which will =
meet the requirements of UL 1459 instead of UL 1950. I understand that =
we can comply with either standard until March 2000 or 2001 and UL 1459 =
is getting talked about around here. Our product is an ISA card that =
will fit into a PC. I would rather go with UL 1950 because the PC would =
be tested to that (right?), because I have heard that we would need to =
install a fuse in the front end to comply with UL 1459 and because UL =
1950 is more compatible with international standards.. My boss is =
looking to save cost so he wants UL 1459 and answers my desire with the =
fact that we will have multiple boards (one for USA/Canada, one for =
international), so we could use this transformer for the domestic board, =
although the issue of whether Canada would accept UL 1459 is not =
resolved. Also, the "fuse", he says, would be the etch on the board =
because they would just peel off with the overvoltage testing of UL =
1459. I am not comfortable with that, though. Anyway, I want to go =
with UL 1950 but I need ammunition. I was wondering if you could help =
me understand the difference between UL 1459 and UL 1950 and also give =
me your recommendation on which to test to. Any help that you can give =
would be greatly appreciated. Thanks in advance.
- Dave Spalding
David Spalding
Motorola ISG
20 Cabot Boulevard
M2-250
Mansfield, MA 02048-1193
Phone: (508) 261-4742
FAX: (508) 339-2346
EMail: [email protected]
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