Hi Folks
My turn to ask some questions as a newcomer to this version of the standard:
1
Dielectric Strength Testing to Clause 6.8.4 "Voltage tests" & Table 9 "Test
voltages for BASIC INSULATION".
Can anyone confirm my suspicion that there may be a misprint in Column 1
"Clearance" of Table 9 , as follows: The line entry between "1.0" and "2.0" is
"1.4" - should this not be "1.5"
(mm)?
That it should be so appears (to me at least!) to be fairly obvious from Table
8 "Clearance
for measurement categories II, III and IV" where "1.5" (mm) is mentioned in
numerous places but "1.4" is not mentioned at all.
Apart from anything else, 1.5mm is the category II minimum value for nominal
line voltages of >150V<=300V - which will be the mimimum value for a very large
amount of equipment.
Otherwise, the majority of users of the standard will have to start out by
interpolating in Table 9 - which is not very clever to say the least, as
mistakes may well occur!
Therefore, even if I am wrong about the need for the "1.4" entry, I think that
the test voltages for 1.5mm should be given as well.
2
This relates to another (this time probable) misprint in Fig 5 "Flow chart to
explain the requirements for protection against the spread of fire".
On the right hand side of the diagram (At least in my copy) there appear to be
arrows missing between the boxes for
i) "Construction requirements for components 9.2.1 a)" and "ENCLOSURE
requirements 9.2.1 b)"
and
(ii) between "ENCLOSURE requirements 9.2.1 b)" and "Requirements for flammable
liquids 9.4 c), d) or e)".
(Obvious I know, but this should not have happened with an important recent
standard).
3
Finally, the Flow chart symbols in this diagram do not appear to conform to
some generally accepted principles, i.e should there not be "decision ("OR")"
box symbols where alternative
routes are available (e.g. as in Fig 10) ?
Comments please - and maybe some corrections to the standard if I am correct.
John Allen
(Ex Thales Defence - but now thankfully with another job after being made
redundant!)
PS
Has anyone checked the OTHER entries in Table 9?
The one above seems wrong, and thus there could be other very errors which
could significantly affect the pass/failure of equipment under test due to
testing at incorrect voltages.
