Wiring Questions 2382

[rustynails]

I'm stumped on this question:

If a fault occurs in the HV system, and a magnitude of fault voltage of 430 volts occurs between exposed conductive parts and earth on the LV installation. What is the maximum tolerable duration of the fault?

10ms
100ms
200ms
300ms

What the heck is the answer and where in the green is book is it?

; )

 

[Silly Sausage]

I had that one last year, it's in the book somewhere!
I'll try and find it again.

edit...

Have a look @ 442, Red book (haven't gone green yet) Should be obvious from the title if it's still the same!

 

[Paul.M]

I'm stumped on this question:

If a fault occurs in the HV system, and a magnitude of fault voltage of 430 volts occurs between exposed conductive parts and earth on the LV installation. What is the maximum tolerable duration of the fault?

10ms
100ms
200ms
300ms

What the heck is the answer and where in the green is book is it?

; )

Appendix 3 mate table 3A.


Archey was so close, its page 243 in my red book and my book only has 389 pages unless I've bought a Eco regs to save paper lol.


Edit, is that the full question? What size mcb/rcd and type is it?

 

[Silly Sausage]

Appendix 3 mate table 3A.


Archey was so close, its page 243 in my red book and my book only has 389 pages unless I've bought a Eco regs to save paper lol.


Edit, is that the full question? What size mcb/rcd and type is it?

Paul, who've lost me there.

I'm going on Section 442, BRB.
I got 300ms from fig 44.2




and I've only had 2 bottles...

 

[Paul.M]

Paul, who've lost me there.

I'm going on Section 442, BRB.
I got 300ms from fig 44.2




and I've only had 2 bottles...

Sorry Archy I thought you did a typo and ment 'page' 242, just next door to appendix 4, Time/current of OPD'S & mcb's. I should also look at the question aswell!


I've been tea total since the weekend! Being sober can't be good for your health .

 

[Paul.M]

And yes it is 300ms.

 

[Silly Sausage]

I've been tea total since the weekend! Being sober can't be good for your health .

About time you got yourself another job young man.

 

[MarkieSparkie]

From BGB, Page 53, Table 41.1 maximum disconnection time with a nominal supply voltage >400V = 0.1s (100ms) for a TN (or TT with dc supply) earthing arrangement.

 

[rustynails]

So the majority of you think its 300ms. It's difficult to read the graph 44.2 or do you use the formula Uf = 0.5 Rf.If

If so is it Uf = 0.5 / Rf x If ???

So that's Uf = 0.5 / Resistance of fault(?) x fault current ??

From BGB, Page 53, Table 41.1 maximum disconnection time with a nominal supply voltage >400V = 0.1s (100ms) for a TN (or TT with dc supply) earthing arrangement.

The test paper says the answer is 300ms.

 

[telectrix]

it's 300mS from table 44.2. somebody get paul a pint in.

 

[rustynails]

I need a pint to read that table?