16th to 17th disconnection times differences

[Lee321]

iirc in 17th all circuits upto 32a are now required to have .4sec dt. even fixed equipment and lighting?

but what was the 16th ?

 

[a1]

Take a peek in your 16th Regs Book.

 

[Lee321]

Take a peek in your 16th Regs Book.

if i had 1 :coat :x

 

[Andy™]

iirc in 17th all circuits upto 32a are now required to have .4sec dt. even fixed equipment and lighting?but what was the 16th ?

5s for distribution and final circuit supplying only stationary equipment

 

[Lee321]

[quote name='Andy

 

[Andy™]

thx andy.and now ALL final circuits are .4 unless above 32a?

yes, for 230v. see table 41.1 (page 46) for other voltages & times

 

[danny7299]

so on the 17th edition forms when it says disconnection time, for cuircuits under 32A its .4 Sec ?

 

[Andy™]

yes, unless its distribution

 

[spinlondon]

Maximum Ze has been lowered in the 17th as well.

 

[Andy™]

Maximum Ze has been lowered in the 17th as well.

?

 

[spinlondon]

[quote name='Andy

 

[Andy™]

Sorry, should be Zs.

they were lowered based on 230v, the old 16th values were 240v

 

[musicspark]

sorry to drag this one up again but I am updating to 17th edition,

what about lighting ?

under 32A but fixed?

 

[loonytoon]

0.4s as under 32a

 

[septiclecky]

Maximum Ze has been lowered in the 17th as well.

Voltage is now 230 and not 240 that is why thet have been lowered.

 

[Andy™]

Voltage is now 230 and not 240 that is why thet have been lowered.

Really?!

cant remember DNO running round changing all transformers to 230v when 17th came out. my house still has 245v

 

[Evans Electric]

Now, now Andy, you know that we all have to pretend that the voltage is 230. Did some tests last week , voltage was 250.

 

[seajayess]

Zs calculation

16th 240 divided by trip current B6 = 30 amps x .75

17th 230 divided by trip current B6 = 30 amps x .80

so

16th Zs 240/30x.75= 6.00 ohms

17th Zs 230/30x.80= 6.13 ohms

hope this helps CJS

 

[batty]

Zs calculation 16th 240 divided by trip current B6 = 30 amps x .75

17th 230 divided by trip current B6 = 30 amps x .80

so

16th Zs 240/30x.75= 6.00 ohms

17th Zs 230/30x.80= 6.13 ohms

hope this helps CJS

Hello cj's have you been on holiday.

 

[seajayess]

Hi all, no moved house late last year and was realy busy at work, then PC got a virus and had to format hard drive and lost all my favorite sites, only just got round to sorting it, but i am back now CJS