does this comply?

[ADS]

Thanks for those who inputed without criticizing me for thinking aloud and considering doing something not in the normal fashion.The bloke at NAPITS response was similar told me it didnt comply, but couldnt tell me why, shortly before hanging up on me.

I cant see how the design effects usability or safety personally.

I can't think of a single reason why you don't put it on a 20A RCBO (as Andy said in post no. 2) - what's with the insistence on a 32A device??

It wouldn't contravene the regs - but what's the point??

 

[batty]

I can't think of a single reason why you don't put it on a 20A RCBO (as Andy said in post no. 2) - what's with the insistence on a 32A device??It wouldn't contravene the regs - but what's the point??

Because he has two machines so could be more than 20 amps but as said this is poor design and poor workmanship.

 

[tom1]

so why not just do 4mm from the start?

 

[Lee321]

so why not just do 4mm from the start?

its just not needed tom.

should have just made it into a ring

 

[ADS]

Because he has two machines so could be more than 20 amps but as said this is poor design and poor workmanship.

Think of cable 1 being a 20A radial feeding a socket outlet.

Think of cable 2 being a spur taken from the origin of said radial, and feeding an FCU.

Perfectly normal practice

If you had a 20A radial feeding 6 sockets - what happens then?

 

[Lee321]

Think of cable 1 being a 20A radial feeding a socket outlet.Think of cable 2 being a spur taken from the origin of said radial, and feeding an FCU.

Perfectly normal practice

If you had a 20A radial feeding 6 sockets - what happens then?

but its not a 20a radial its a 32a one on 2.5

 

[ADS]

but its not a 20a radial its a 32a one on 2.5

I know - and I'm asking him why? - when a 20A device is the normal way of doing it.

I just don't get the reasoning behind the question.

 

[Lee321]

I know - and I'm asking him why? - when a 20A device is the normal way of doing it.I just don't get the reasoning behind the question.

my bad

prob due to cost of 2 rcbo's :run or space

 

[kme]

But it wouldn`t NEED 2 RCBo`s - unless diversity says otherwise???

And if it does, the design of the circuit isn`t too good. If I PIR`d that, I`d be looking for a downgrade to a 25A min; preferably a 20A.

Or....Feed them as spurs from two seperate, low-loaded radials.

My opinion, anyway.

 

[Lee321]

was making a presumption <50mm kme

 

[Badger]

Disagree; and here`s why:You don`t have a ring and a spur, you have 2 radial ccts, on 2.5mm, protected by a 32A OCPD.

It doesn`t comply. Pure & simple. Sorry, I`m with the technical dept. on this one.

Even if it didn`t contravene a reg, I`d consider it bad practice.

KME

:Applaud :Salute

 

[PC Electrics]

I think that this is extremely borderline. On the one hand it would seem to comply because overload protection is at the socket / fcu. On the other is it two radials really and the cables are not protected?

In such a case I would revert to known territory and put these on a 20A. A 20A MCB is plenty sufficient to supply two items with variable load eg a washer and dryer next to each other. Both appliances only pull full load intermittantly as heating elements switch in and out. Also from the curves page 249 BRB 30 amps would take 1000+ seconds to trip a 20A MCB (that's 15 mins).

No design problem with 20A - all cables protected, comliance isn't in question - job jobbed and you're on safe ground.

(note that the machines in question are not specified)

 

[ianmacd]

[quote name='Andy

 

[Lee321]

You can not tell that as no distance from the RCBO so if its over 3m it will not comply. Also should be considered as a 2.,5 radial so OSG says (I hope not got it infront of me) that a 32A protective device is not permissable.

don't get you ian. the cable will carry 13a whether its 1m long or 100

 

[ianmacd]

[quote name='Lee

 

[Lee321]

Regs say max 3m if using upstream protection.

hmmm. yes i'm with you altho that normally is applied to a senario of tapping off a 600a busbar system with 1.5 for example. hmmm ponders for a while

edit to add: thats only for fault protection again not overload. ?

eta:433.3.1(ii)

 

[sparkytim]

BRB Pg 74

433.2.2

(ii) 3 mtrs max

 

[Lee321]

BRB Pg 74433.2.2

(ii) 3 mtrs max

only when there is a change in current carrying cap

which this scenario does not step down

 

[ianmacd]

[quote name='Lee

 

[wozz]

I think that this is extremely borderline. On the one hand it would seem to comply because overload protection is at the socket / fcu. On the other is it two radials really and the cables are not protected?In such a case I would revert to known territory and put these on a 20A. A 20A MCB is plenty sufficient to supply two items with variable load eg a washer and dryer next to each other. Both appliances only pull full load intermittantly as heating elements switch in and out. Also from the curves page 249 BRB 30 amps would take 1000+ seconds to trip a 20A MCB (that's 15 mins).

No design problem with 20A - all cables protected, comliance isn't in question - job jobbed and you're on safe ground.

(note that the machines in question are not specified)

Quite right it could easily sit on a 20A, i wasnt as suggesting it had to be on a 32A but i could see it not complying either.

Im glad people are discussing the point i raised and quoting regs and not just criticizing me, i asked if it complied, i didnt say this is the best designed circuit ever.

And it clearly is not as clear cut as some was suggesting...