Randy,
Regarding your question # 1, be careful with fuse selection. Some of
the 5 X 20 mm fuses have a current interrupt rating of only 35 Amps.
I don't know of any specific fuses that will meet the universal
requirements, perhaps the local Bussman, Littlefuse, or Gould-Shawmut
rep can help.
Regarding your question # 2, look at Paragraph 6.1.1 "Exceptions".
Terminals and sockets of operating and measuring circuits, if it is
unavoidable for operating reasons that they are both ACCESSIBLE and
HAZARDOUS LIVE ARE PERMITTED TO BE accessible to the OPERATOR during
NORMAL USE. I presume that you are referencing Paragraph 6.5 Note 1.
If you read further you are allowed to select one of several solutions
for protection in a SINGLE FAULT CONDITION. There is no requirement to
bond Terminals to ground for the same reason that there is no
unremovable cover on the blade of a meat slicer. Neither is very
useful unless the "working" end is available.
Hope this helps. While I was at FLUKE I had the privilege of working
with Walt Hart, one of the principal authors of IEC 1010-1. Walt was
able to provide great insight into the standard and the rationale and
history of many of the clauses. I offer the above information with
the disclaimer that I give my opinion only and that it is not binding.
Best regard,
Dan Teninty PE
Hughes Missile Systems Company
Tucson, AZ
[email protected]
______________________________ Reply Separator _________________________________
Subject: Fuses & Switches
Author: Randy Stephens <[email protected]> at CCGATE
List-Post: [email protected]
Date: 4/17/97 2:50 PM
I have two simple questions:
1) I have equipment which will be tested according to IEC 1010-1. This
particular piece of equipment requires a mains 10 amp fuse at 230V line.
I looked at some fuse manufacturers and they have fuses rated for what I
need, but aren't necessarily IEC approved or are not approved for
certain countries (like Denmark only accepts up to 8 amps when using IEC
127 fuses). Are there any fuses which are approved for all countries
which can handle the current requirements? I would prefer using the
standard 5 mm X 20 mm size fuse.
2) This same piece of equipment will produce an accessible hazard
in-order to fulfill it's proper function (20 kV and 30 mA). IEC 1010-1
states that I need an emergency switch. Does this switch have to shut
down all the power to the equipment (break the mains), or can I use it to
break power just to the Hazard generating circuitry? This would allow me
to allow the cooling fans and some low voltage ( less than 15 volts peak)
circuitry to remain active. Or, can I use it to activate an opto-coupler
and/or a solenoid device which would break the power for the unit?
Any help would be appreciated. Thanks in advance.
Randy Stephens
Electrical Engineer
Trek, Inc.
Medina, New York
