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# Regs guide typo or not? - what is allowed disconection?!

Discuss Regs guide typo or not? - what is allowed disconection?! in the Electrical Forum area at ElectriciansForums.net

I

#### Inteificio

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For disconection times we have to hit 0.4 for up to 230v U0. 0.2 for 400-1000U0.

I always took this to mean what it says.

both single and 3 phase V to earth is 230, so we use the 0.4 disconection.

Taking my 17th update and got told that was a typo!!!!

So for 3 phase we are supposed to use 0.2, single 0.4.

Now that is not what the book says!

So what am I supposed to design my circuits for?!

The question is partially moot as I always use MCBs so they knock off in 0.1, but that is not not the point.

When I chuck in my next 88, what should I desgin it too?

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#### kingeri

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Arms
A typo in the BGB? Which page/reg are you referring to?

#### i=p/u

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Arms
only thing changes dis times is tt, 230v to earth, dont hink mentions fault between phases

K

Given that the power dissipated in a phase to phase fault is 3 times that of phase to neutral a faster disconnection time makes sense.

#### IQ Electrical

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For disconection times we have to hit 0.4 for up to 230v U0. 0.2 for 400-1000U0.

I always took this to mean what it says.

both single and 3 phase V to earth is 230, so we use the 0.4 disconection.

Taking my 17th update and got told that was a typo!!!!

So for 3 phase we are supposed to use 0.2, single 0.4.

Now that is not what the book says!

So what am I supposed to design my circuits for?!

The question is partially moot as I always use MCBs so they knock off in 0.1, but that is not not the point.

When I chuck in my next 88, what should I desgin it too?
There is no 'typo' it's 0.4 seconds and it is Uo.

#### widdler

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Mentor
Arms
There is no 'typo' it's 0.4 seconds and it is Uo.
Agreed.

The only typo I have found so far is in the OSG.

#### IQ Electrical

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Agreed.

The only typo I have found so far is in the OSG.
Page 144?

D

#### Deleted member 26818

There's always Reg. 634.2, got a ',' after the word Regulations which shouldn't be there.

#### IQ Electrical

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There's always Reg. 634.2, got a ',' after the word Regulations which shouldn't be there.
Well if that's not adequate grounds for a refund, I don't know what is!

I

#### Inteificio

Sorry for the late response. forgot to subscribe to this thread so didnt know there were any responses.

If it is not a typo then why the split?

I can undestand 230-400-1000v as that would be single phase, 3 phase and high voltage.

So why do they split it Uo for 230 400 and 1000?

Regs book is in the car so can't quote precise reg yet.

Just took my 17th 1st edition update today, there are quite a few changes!

#### widdler

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Mentor
Arms

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