Rating of Flexible cable

[EFLImpudence]

Aren't we talking about the CCCs listed in BS7671?

Such conditions could easily be listed - as they are for all other cables and sizes.

 

[JohnW2]

Aren't we talking about the CCCs listed in BS7671?

WE are (well, at least, I am!) - namely Table 4F3A.

Such conditions could easily be listed - as they are for all other cables and sizes.

As I said before, I don't think they could in any useful way ...

... unlike the situation with 'fixed wiring', the 'environmental situation' (c.f. 'installation Method') with 'flexible cables' is not fixed. Much of the flex of my other half's iron could be in free air today, under a massive pile of laundry tomorrow and, at least hypothetically, 'under the carpet' the day after. As I said before, the only thing I can think that one can do in such a situation is to 'rate' the cable on the basis of the perceived 'worst case scenario'.

Kind
Regards, John

 

[plugwash]

Aren't we talking about the CCCs listed in BS7671?

Some people are, but I don't see how it's a relevant standard, BS7671 is a standard for electrical *installations* in the UK. Not a standard for portable equipment.

I just checked BS-EN 60950-1-2006 table 3B which specifies minimum sizes for IT equipment power cords and it does indeed say that 1.0mm flex can be used for detatchable power cords up to 2m in length with 16A rated connectors.

I don't know why the IEC made this exception to the normal flex sizing rules, but it seems to be an indisputable fact that they did.

 

[mattylad]

Some people are, but I don't see how it's a relevant standard, BS7671 is a standard for electrical *installations* in the UK. Not a standard for portable equipment.

I just checked BS-EN 60950-1-2006 table 3B which specifies minimum sizes for IT equipment power cords and it does indeed say that 1.0mm flex can be used for detatchable power cords up to 2m in length with 16A rated connectors.

I don't know why the IEC made this exception to the normal flex sizing rules, but it seems to be an indisputable fact that they did.

I say the very same thing at work where I have to work with aged/failed electricians who got jobs as electrical assemblers, BS7671 is not applicable to the manufacture of appliances - only the installation of it.
Have a look in the first few pages of 7671 around the "Scope" where it specifically says so.

EN60355 is the standard for manufacturing equipment for use in domestic and other locations.
So far I have not seen any tables for calculating cable sizes in there and I do have all parts of 60355.
While I'm not reading them all, it seems that where I work I am the only one that reads it at all

 

[EFLImpudence]

I realise that appliance flex does not come under 7671, but as flex can be used for fixed wiring, then the CCCs in 7671 should be accurate.

No one seems to really know why the CCC Is so much lower than other types of cable.

 

[JohnW2]

Some people are, but I don't see how it's a relevant standard, BS7671 is a standard for electrical *installations* in the UK. Not a standard for portable equipment.

Indeed - but, as EFLI has said, the CCC figures in BS7671 do apply if flexible cable is used as part of the fixed wiring in an electrical installation - and, has he has also said, it is not clear why the CCCs for such cables (when used in such ways) are so much lower than for the same CSA of non-'flexible' cable.

Kind Regards, John

 

[SUNRAY]

In October I went back on this job... to replace the 2x300W fittings with Clipsal infrascan 50W. Thinking now about the other threads recently about underrated/unprotected cables I didn't remember if I gave the original outcome.
I did install 2 of the shorter 1.0mm² cables (the 2 that were easy to get to) and sure enough they did get hot and deform. I sent them back asking for a full refund as faulty along with the other (I think) 6 which were still sealed in their packs... carefully identity marked my myself. Included in the package were prints of the 11 messages we'd shared and a photo of the way I'd marked them.
They sent me a full set of replacements 'under warranty' including those I'd marked. Several phone calls followed which got me nowhere until i managed to get through to a 'senior manager' who listened to my summary of events and he made the decision to fully refund the invoice and promised to look into it fully, of course I never heard anything more after receiving the refund.

In the mean time I'd sourced from another supplier, they sold them in 2 flex sizes: 1.5mm² or 2.5mm². Admittedly the price was higher by ~50% & ~100%, as these were to run at 16A I chose the bigger size.