Touch potential calculations/test

[lielec11]

Anyone know what type of calculations are involved for a touch potential test? Client of mine had a requirement come across their desk and I've never performed anything like that. Now I am curious as to what is actually involved in the calculations and field tests in determining the touch voltages.

 

[zog]

Outdoor substation? IEEE Std 80

 

[Julius Right]

Earthing of power installations exceeding 1 kV a.c,
BS EN 50522/2010 or IEC/CENELEC EN 50522/2010(E) Annex H.
For indoor or outdoor installations.[ See ch.1 Scope for what is considered by this standard as electrical power installation.]
For substation outdoor installations:
IEEE Std 80-2013
IEEE Guide for Safety in AC Substation Grounding
19.2 Field survey of potential contours and touch and step voltages

 

[Sahib]

I wonder whether NEC requires any touch potential calculation/test. I believe it does not.

 

[lielec11]

I don't believe so but it was listed as a requirement from the local utility company for this specific project. To be honest it's the first I've seen for a traditional 15kV-480V step-down indoor switchgear.

 

[zog]

To be honest it's the first I've seen for a traditional 15kV-480V step-down indoor switchgear.

Yep, that would be out of the ordinary.

 

[Sahib]

Then the local utility company may be approached for a model touch potential calculation and test procedure because it is their requirement.