Calculating external R1 & R2

[allybally]

Is there any way of calculating the r2 and r1 values of Ze for touch voltage calculations

many thanks

 

[uksparks]

Eh????

 

[shanky887614]

Why do you need external r1+r2.

r1+r2 is easy to calc

 

[Hawkmoon]

You could test the impedance L to N first - half this value presumably will be R1
Then test Ze - minus R1 off the Ze value to give you R2

It's late though so I may be talking complete tripe lol

What touch voltages are you concerned with? rods?

 

[SirKit Breaker]

The supply nominal voltage will either be 230V or 400V, you will never get a supply at 50V or less!

Your measured Ze is your external R1+R2 (although such a thing in terminology doesn't exist), think about it, and the penny will drop.

Cheers…………Howard

 

[Hawkmoon]

The supply nominal voltage will either be 230V or 400V, you will never get a supply at 50V or less!

Your measured Ze is your external R1+R2 (although such a thing in terminology doesn't exist), think about it, and the penny will drop.

Cheers…………Howard

Agreed - never considered external Ze as R1 + R2, but he did ask politely so attempted to help - though as often the case the OP has scarpered lol

 

[R G]

Ze is obtainable by measurement or enquiry to the DNO , don't know why you want R1 R2 of Ze , unless you are installing the transformer , I suppose if you are installing a private transformer it would be a consideration ,,,

 

[SirKit Breaker]

Ze is obtainable by measurement or enquiry to the DNO , don't know why you want R1 R2 of Ze , unless you are installing the transformer , I suppose if you are installing a private transformer it would be a consideration ,,,

I think we are in danger of getting too complex with this. And i think the OP maybe on a windup. The Ze is in effect the supply (R1+R2), R1 (supply line conductor), R2 (Supply earthing conductor), as these two items are the main component parts of the External Fault loop path (Ze), but they are not referred to as R1 or R2.

Some one is getting their wires crossed, non pun intended :smiley2:

 

[allybally]

Hi this post is not a wind up and I understand r1 & r2 internally, but I was reading up on touch voltages and the formula involved the resistance of r2 and the external earth resistance and from that touch voltage was calculated, the book is guidance note 8, they refer to the external r1 and external r2 and the transformer resistance as Ze so broken down, but there is no clear answer as to how they got the resistance values (broken down) for this as r2 is the only only needed

 

[telectrix]

no such thing as r1 and r2 on a supply. it's not a ring, is it?

 

[shanky887614]

no such thing as r1 and r2 on a supply. it's not a ring, is it?

Next he is going to ask how to work it out on a radial

 

[Hawkmoon]

no such thing as r1 and r2 on a supply. it's not a ring, is it?

lol, nothing gets by you tel

 

[allybally]

Listen I'm just trying to learn about something different and all you lot do is try and be all high and mighty, why don't you read guidance note 8 and the touch voltage part and see if you can understand it and understand why I'm asking the question on here, or should I just down grade my qualifications and become a site sparky!!!!

no such thing as r1 and r2 on a supply. it's not a ring, is it?

 

[Hawkmoon]

Listen I'm just trying to learn about something different and all you lot do is try and be all high and mighty, why don't you read guidance note 8 and the touch voltage part and see if you can understand it and understand why I'm asking the question on here, or should I just down grade my qualifications and become a site sparky!!!!

I think tel was referring to your use of lower case r - rather than higher case R.

These have different meanings you may remember - think it was in jest rather than being 'high and mighty'

 

[MDJ]

Listen I'm just trying to learn about something different and all you lot do is try and be all high and mighty, why don't you read guidance note 8 and the touch voltage part and see if you can understand it and understand why I'm asking the question on here, or should I just down grade my qualifications and become a site sparky!!!!

Calm down and take a deep breath, think about your first post here then read Howards reply and then think about it, the guys have been very calm actually in this post, chin up.