mm2 ampacity restrictions

[Gardner]

Under BS7671, what is the amperage of 1.5mm2, 2.5mm2 and 4mm2 copper conductor restricted to when inside a race way or cable of no more than 3 current carry conductors? Thank you! :smiley2:

 

[Gardner]

Do you have a copy of BS7671?

I have a PDF from the internet, at least I believe it to be correct.

 

[Guest55]

"raceway" ?
"pvc jacketed" ?

pfft , next you'll be calling a rcd a ground fault circuit interupter or some such nonsense......... ;-)

 

[Gardner]

"raceway" ?
"pvc jacketed" ?

pfft , next you'll be calling a rcd a ground fault circuit interupter or some such nonsense......... ;-)

:lol::lol: You know us well! Our RCDs for personal protection trip at 5 milli amps and we call them Ground Fault Circuit Interrupters (GFCI). We also have 30ma RCDs in rare cases but are called Equipment Ground Fault Protection (EGFP), since they do not protect people. At least by our standard, since anything over 5ma is considered not to be people protection. I know, strange way to have it...

In fairness to him he is talking about our sizes of cable (not awg), i think he is just trying to get a grasp of our cable relevant to his own yank cable.

For now thats what Im thinking. My noodle is trying to wrap around it. I have some experience with IEC wiring practices because of imported machines but still lack luster. All my knowledge and training has been around the NEC, UL and ANSI (all American standards)

Possibly Rapparee but my post will give insight as to what we need to know to answer his question, not knowing the American way its hard to approach this with any other answer unless the OP gives more detail or expresses why he's after this info..

If it helps this is probably the most commonly used NEC table for indoor and buried wiring methods. 14 gauge is restricted to 15amps, 12 guage is 20amps and 10 gauge is 30amps. Above 10 gauge either the 60 degree column may be used or the 75 degree depending on the cable and termination temperature rating of the device (most are 75*C rated now a days).

 

[rapparee]

Table 4D2A – Multicore 70c thermoplastic insulated & thermoplastic sheathed cables (e.g. PVC T&E), non-armoured.* All values assume an ambient temperature of 30c and a conductor operating temperature of 70c.*


Im assuming reference method a


1.5mm = 14A

2.5mm = 18.5A

4mm = 25A

 

[Gardner]

Thanks!

Im having trouble inserting pics but here is 310.15 B 16 (formerly 310.16) from the NEC just to give you guys an idea how the 2 might compare:


http://mooreu.com/0_moore_art/2011_NEC_National_Electrical_310.15_Ampacity_Table_750w_1079h_2.gif

 

[Engineer54]

More to the point, what receptacles and light switches are you providing?? I ask because your conduit sizes are larger than Europe's metric sizes and therefore will not connect easily, if at all to BS wall outlet/switch back boxes. Your 120 volt receptacles and light switches won't be acceptable. Come to that, what DB are you installing, as i can tell you now the MCB's will need to comply with BS time/current standards rather than those of American standards that are wildly different.

Oh, and for god sake ''DON'T'' use any of your ''wire-nuts'' within this mobile trailer/building, they are not a generally recognised means of cable connection in the UK or Europe...

 

[SparkyJoe]

fire nuts, what a **** idea they are.

 

[Gardner]

This is one of the suppliers, or at least one we very commonly rely on for export applications:

INTERNATIONAL CONFIGURATIONS,CORDSETS,CORD SET, DETACHABLE CORDSETS,IEC60320, IEC320, IEC60309,IEC309,PLUGS,OUTLETS, SOCKETS,PLUG ADAPTERS,RECEPTACLES,OUTLET STRIPS,POWER STRIPS - INTERNATIONAL CONFIGURATION.

Legrand, Schneider electric ect will also be used. FWIW in America we do have 277 volt switches since our large commercial and industrial is 277/480Y, so if need be those would interrupt 230 volts without issue.

Sockets will be BS 13amp types fed most likely from a ring main or radial. Radial will probably win since ring main scare me, and most other working with this (no offense). If any schuko plugs are needed those automatically get 2.5mm2 cable at either a 16 or 20amp RCBO since schuko has no built in fuse.


Just to ask, why are wire nuts not recognized in the EU? When pre-twisted and done right they are an indestructible connection.

 

[Gardner]

fire nuts, what a **** idea they are.

Same could be said about ring mains and having 240 volts phase to ground at domestic equipment.








:lol::lol: I tease in good fate. The EU system wins with RCD requirements.

 

[ayjay]

origional poster
forget posting here
go to an american site

 

[ayjay]

 

[Gardner]

origional poster
forget posting here
go to an american site

Yes, because an American site will exactly have British electricians that know what I am doing.

FWIW over on Mike Holt and Electrician talk.com (both American forums) Electricians from India, Australia, Canada, China, even France, ect come visit us... and we more than gladly explain to them how to work with the NEC and its applicable standards. I have many times.

BTW, last I checked North Korea is not all that very close to the UK...

 

[Engineer54]

Just to ask, why are wire nuts not recognized in the EU? When pre-twisted and done right they are an indestructible connection.

UK stopped using ''Screwits'' our version of wire nuts more than 30+ years ago, they were as is your wire nuts are today, the cause of many a fire, (check out the major cause of electrical domestic fires in the USA) All connections are now made with screwed/clamp type connections or with the use of MF (Maintenance Free) Wago type connectors or insulated crimp connectors....

Let me put it this way, i got handed a project in the Middle East that's specification was based around and on NFPA 70 (NEC), where wire-nuts were used profusely (as in all US electrical installations) During the inspection and testing program as well as during the 1 year warranty period it was problem after problem with these wire-nut connections (many from broken conductors due to over tightening) It got to a point during that warranty period, that all these bloody wire-nut connections were replaced with screwed and crimped connections. Funny how the ongoing problems started to decrease almost immediately. The size of your wire-nuts are not suitable for the much smaller UK/EU wall accessory back boxes either. Personally i wouldn't allow and haven't allowed them to be used on ANY job or project that i've been involved with or on...

 

[Engineer54]

If any schuko plugs are needed those automatically get 2.5mm2 cable at either a 16 or 20amp RCBO since schuko has no built in fuse.

The German Schuko version are also a non polarised plug and outlet (scraping earth), whereas the almost equivalent French version is polarised via a protruding earthing pin on the wall accessory plate (receptacle) Both German and French tend to use DP or SP+N MCB's and RCBO's....

 

[Besoeker]

A couple ot three comments in no particular order.

Wire nuts went under the name "Scruit" not screwit - that's a whole different thing. Particularly if you spell whole incorrectly. Scruit was/is a trade name IIRC.

RS Components and others still supply them.

As far as I can tell, they are not illegal in UK. I see nothing in BS7671 that proscribes their use

No, I haven't seen them used in at least 40 years. In any case, the need for them has largely gone away. Fittings have screw terminals on which to land conductors that just need to be connected together.

And the mention of amperage (a horrid non-word IMHO) in the opening post was a pretty good clue that the poster was American. Yank? Maybe not. That would depend on which side of the Mason-Dixon line he's from.

My sweet Southern Belle would be quite offended, horrified even, to be called a Yank.