What resistance should grounding have?

What resistance should grounding have? This is the right question everyone thinking about electrical and fire safety should ask.

This manual contains all necessary standards on resistance; it helps you to arrange grounding loop with the required parameters.
Add to your favorites!
Reference values of resistance of grounding loops:

Object/system	Reference value (not exceeding)	Normative act	Recommended grounding kit
1. Private houses with connection to power lines 220 V/380 V:
1.1 TN-C-S system	30 ohms	Electrical installation code 1.7.103	ZZ-6 ZZ-000-015
1.2. TT system	30 ohms	Electrical installation code 1.7.59 and 1.03-08	ZZ-6 ZZ-000-015
2. Substation, 110kV	0.5 Ohm	Electrical installation code 01/07/90	ZZ-000-015 ZZ-000-030 ZZ-000-045 ZZ-100-102
3. Telecommunication equipment	2 or 4 Ohm		ZZ-000-015 ZZ-000-030 ZZ-000-045 ZZ-100-102
4. Air communication lines	2 or 4 Ohm		ZZ-000-015 ZZ-000-030 ZZ-000-045 ZZ-100-102
5. Power source, e.g. transformer substation (with linear voltage of 380 V, three-phase supply, or 220 V, one-phase supply)	4 Ohm	Electrical installation code 1.7.101	ZZ-000-015 ZZ-000-030 ZZ-000-045 ZZ-100-102
6. Grounding with connected lightning rods	10 Ohm**	RD 34.21.122-87	ZZ-000-015 ZZ-000-030 ZZ-000-045

* With residual current devices ** Impulse resistance to spreading of lightning currents

You can make use of:

Webinar Titled "Online Calculation of Lightning Protection for An Explosives Warehouse"

Functional Grounding for a Football Stadium in Sochi

Lightning Protection and Grounding for a Preschool Education Facility (PEF)

Webinar "Dangerous Discrepancies in Regulatory Documents for Lightning Protection of Explosive Facilities"