Diesel tank earthing above ground

[Pieter00]

Hi guys, I have to go out and quote on a diesel storage tank earthing. Now I assume it will be for lightning which means a risk assessment must be done and soil resistivity must be done to calculate the appropriate earthing needed. Now firstly, I’m not a master electrician, just an installation electrician. I’m 100% sure this would fall under a master electrician’s description correct? Would you do this earthing installation if the installation comes with drawings and specs provided by the electrical engineer even if you are not a master electrician? And what if the specs tells you the Earth conductor size they want to be used etc without any risk assessment done to show that X amount of Earth rods must be installed at X meter deep or a Earth ring must be installed.

[GCE]

The earthing of a diesel storage tank would fall under Hazardous areas and SANS 10089-2 would come into play along with a couple of others

The earthing is not straight forward and takes into account static , cathode , lightning etc

If you are doing the work under the supervision of a Master electrician than I don't see a problem.
Ensure that you make it clear that you cannot sign off a coc for the installation.

Pasted some of the references to earthing from SANS below

8 Cathodic protection
8.1 General
8.1.1 Impressed current cathodic protection systems are widely used in the petroleum industry to
prevent corrosion and are described in more detail in SANS 10121.
The use of cathodic protection in the petroleum industry for the prevention of corrosion of tanks and,
pipelines, manifolds, sea lines, jetties, etc., could introduce hazards when this method of corrosion protection
is used in hazardous locations.

9 Requirements for earthing and bonding
9.1 The equipotential earthing system
a) Electrical apparatus shall be connected to an earthing system that will provide a low earth loop
impedance path for quick clearing of faults. Follow the requirements of SANS 10086-1 in this
regard (see annex C).
NOTE These requirements are often stricter than those in SANS 10142-1, as SANS 10142-1 addresses
only electrocution hazards and the prevention of ignition sources that are capable of igniting explosive
atmospheres.
b) In addition to the electrical safety earth provided to comply with SANS 10142-1 (for example the
“spare core” earth), a second earth connection should be provided to each item of electrical
equipment to prevent the potential to earth of such equipment rising above spark potential (see
annex C).
c) Earth all extraneous and exposed metal parts in the same manner as described in 9.1 (b).

9.2 Lightning protection
The principles given in SANS 10313 should be applied.
Vertical type steel tanks connected to piping and resting on ground have proved to be sufficiently
earthed for the safe dissipation of lightning strikes. Special circumstances could arise due to the use
of non-conductive secondary containment systems where additional lightning protection might be
required.

9.5 Static electricity and bonding
9.5.1 Some of the recommendations for minimizing static electricity and hazardous practices
associated with static electricity are listed below.
9.5.2 Fluids in motion generate static electricity. The rate of charge generation depends on the
conductivity of the liquid, its purity and degree of agitation.
NOTE A comprehensive treatment of static electricity and its limitation as is applicable to the petroleum
industry is given in recommended practice API 2003 and the IP Code – Part 21

[Pieter00]

Thanks, so the installation also consists of giving power to the pump. Another 2!contractor t know was with me on the RFQ told me they just change in the coc from IE to MIE and the one contractor did a previous job like that already with H07 cable powering the pump and 1 Earth rod with 16mm earth 😒 I told the client I can’t sign off on this as I’m not an MIE and he said I must still quote as they require 3 quotes. I’ll be addressing this matter today with the people in charge regarding the other contractors