Are US and Canada cable insulation standards so low compare to EU or what? - Page 1
Forum section: electronics / projects

author: Kjelt
author_rank: Super Contributor
timestamp: July 13, 2015, 06:32:36 pm
content: just read this datasheet from 3M for a ribbon cable they sell.What I found astonishing are the specifications of this cable, in the USA and Canada it is rated for 300V but for Europe less than 50V a factor 6So is this correct and are the insulation requirements in the USA and Canada so low or what?

author: Richard Crowley
author_rank: Super Contributor
timestamp: July 13, 2015, 07:06:47 pm
content: Seems much more likely that the EU "standards" were set by faceless government bureaucrats and not established on any actual scientific or engineering principles.

author: IanB
author_rank: Super Contributor
timestamp: July 13, 2015, 07:08:39 pm
content: In the USA mains cords are allowed to have a single layer of insulation over the conductors (i.e. "figure 8 zip cords"). In Europe you don't see this any more. I suspect this would be the difference in the voltage rating: single insulated vs double insulated.

author: German_EE
author_rank: Super Contributor
timestamp: July 13, 2015, 07:10:37 pm
content: The first thought that comes to mind is maybe the specification is different for the EU and American tests. As an example, one may specify the breakdown voltage with little or no current being passed and another may do the test with the cable under maximum load. We even see differences here in the EU, when specifying maximum current capacity you will see one value for free air/cable trays and another (lower) current value when a cable is used in conduit or trunking.

author: dom0
author_rank: Super Contributor
timestamp: July 13, 2015, 07:16:34 pm
content: I suspect it's just a data cable and they did simply not test the IEC/EU standards for mains voltage, so they limit it to SELV.As IanB noted all mains carrying cables the user can touch must be doubly insulated here, but single insulation is of course ok for internal wiring.

author: langwadt
author_rank: Super Contributor
timestamp: July 13, 2015, 07:20:40 pm
content: it is probably just because above 50VAC/75VDC you have to comply with the EU low voltage regulations

author: wkb
author_rank: Super Contributor
timestamp: July 13, 2015, 07:22:02 pm
content: Quote from: Richard Crowley on July 13, 2015, 07:06:47 pmAnd there ain't any of that breed over in the US?Interesting.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: July 13, 2015, 07:44:50 pm
content: American approach: Specify the guaranteed failure point. Use your judgement about how high to run it.European approach: Specify the guaranteed safe operating point. Use your best guess about the margin past this point.

author: langwadt
author_rank: Super Contributor
timestamp: July 13, 2015, 08:18:39 pm
content: Quote from: Tomorokoshi on July 13, 2015, 07:44:50 pmyeh something along the lines of: functional rating vs. safety rating

author: Richard Crowley
author_rank: Super Contributor
timestamp: July 13, 2015, 09:25:33 pm
content: Quote from: wkb on July 13, 2015, 07:22:02 pmOh yes, of course there are. And we are becoming more "European" every year. Why here in my corner of the Colonies, we "love" our government so much, we have an EXTRA layer of bureaucracy. 6 layers of government if you count the UN.But I think @Tomorokoshi had the best explanation.

author: miguelvp
author_rank: Super Contributor
timestamp: July 13, 2015, 09:34:49 pm
content: Double insulation in the US is only required for Class II appliances that don't connect to earth ground.For trays, etc, we call that plenum and there is a requirement to use plenum wiring (even for ethernet) but that only has to do with fire retardation, so that the wiring doesn't spread the fire faster.

author: SL4P
author_rank: Super Contributor
timestamp: July 13, 2015, 11:00:40 pm
content: Plenum cabling is frequently a lower cost conductor arrangement (e.g. solid core) for fixed installation that doesn't have to meet (e.g. multi-stranded) flex requirements needed in 'flex' applications.In CAT-x terms - plenum cabling vs patch (flex) cables.

author: miguelvp
author_rank: Super Contributor
timestamp: July 13, 2015, 11:08:42 pm
content: I should have stated "in the US" twice, in here it has to do more about fire safety than anything else.