Touch voltage to earth

[pc1966]

HELP!! Attachment wont download for me. Any advice very welcome.

Still works for me (Firefox on Linux PC), but I expect any desktop should work. Are you using a phone to view things?

 

[LastManOnline]

Still works for me (Firefox on Linux PC), but I expect any desktop should work. Are you using a phone to view things?

Tablet. But I will give the desktop a go. Thanks ?

 

[littlespark]

It’ll have ended up in some “downloads” folder somewhere. You got to go look for it.

 

[pc1966]

Probably the folder with "beware of the leopard" on it.

 

[LastManOnline]

It’ll have ended up in some “downloads” folder somewhere. You got to go look for it.

Yes. It kept saying download failed but I will take pc1966 advice. Thank you

 

[Jako13!]

During a fault you will get the supply volts times R2/(R1+R2) relative to true Earth where R1 includes the supply phase impedance, and R2 includes the supply ground.

But it is complicated by the other aspects such as any water/gas bonding to metallic pipes that might raise the local earth where you are standing up a bit relative to true Earth.

So you can see voltages from around 1/2 supply (on long supply cable with R1 around R2) to close to the supply (if R2 is very high on TT system). But the danger of serious impact also depends on the exposure time, hence the values of 0.4s (typical LV TN-S) and 0.2s (TT) for max disconnection to try and keep the likely current-time exposure down.

If you are unfortnuate enough to be in good contact, say a swimming pool , then the current can be much higher even though a similar disconnection time is likely. Hence the requirement for SELV in that sort of high risk area as an RCD limits the exposure time, not the actual current, you might get.

So basically it’s the difference between the raised voltage of the installation when the fault occurs the the true earth we may be standing on that determines the voltage?

 

[LastManOnline]

See this attachment for the long answer...

Can anyone give me the name on this link. Can't download it for some reason so hoping to just Google it?

 

[loz2754]

Can anyone give me the name on this link. Can't download it for some reason so hoping to just Google it?

https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781444324273.app01

 

[LastManOnline]

https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781444324273.app01

?. Much appreciated

 

[Vortigern]

Any advice very welcome.

My advice is leave it at that! Reading it will give you a headache )