Welding Plug Earth Leakage

**BobZA** · 19-Apr-22, 01:07 PM

HI All,

Looking into power supply to client's 400V 20A 3P+E welding plug. I would appreciate some thoughts on the following:

It seems clear that according to SANS10142 we do require "earth leakage protection if the circuit is intended to supply portable or stationary class I appliances". What is not clear is the size of the earth leakage. The 30mA requirement seems to cover only the normal 230V 16A sockets ... but what about the Welding Plugs? I know in the past 30mA can cause nuisance trips for Welding Machines etc..

What do you guys use for Welding Plugs earth leakage units ?

Thanks In Advance ...

**Dylboy** · 20-Apr-22, 06:49 PM

Hello

Below states a 30mA, it copied more than what i wanted but phone giving issues.

7.4.6.5 The metalwork shall be protected against corrosion and the damage
expected under site conditions. The final finish shall be orange.
7.4.6.6 Isolating devices shall be suitable for securing in the off position (for
example, a padlock or location inside a lockable enclosure).
7.4.6.7 The distribution board shall contain
a) one or more multi-element robust LED indicator lamps per phase to show
that the board is alive. HRC fuses or correctly rated circuit-breakers within
the board shall protect these lamps,
b) where required, four-pin (three-phase and earth) welding socket-outlets,
typically 63 A rating, each of which shall be protected by a circuit-breaker
and 30 mA earth leakage protection,
c) where required, three-pin (phase neutral and earth) welding socket-outlets
rated at 32 A with associated circuit-breakers and 30 mA earth leakage
protection. This shall particularly be provided for portable single-phase
welding sets, and
d) switched socket-outlets (16 A), connected in pairs to individual single-pole
20 A combined circuit-breakers and 30 mA earth leakage protection of
sufficient number.
7.4.6.8 The circuit-breakers and associated earth leakage relays referred to

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**GCE** · 21-Apr-22, 05:27 AM

Hi BobZA

The regulations pasted by Dylboy are relevant to construction sites

Reg 6.7.5 is relevant to your particular question
6.7.5 deals with single phase and 3 phase socket outlets and stipulates 30mA earth leakage to be used ( pasted below)

To prevent nuisance tripping use a earth leakage per socket outlet or every 2nd one. We use integrated ELU with overload protection to save space in the D/Boards.

The majority of time that we have been asked to look into nuisance tripping there have been multiply socket outlets on 1 unit and the accumulation of leakage to earth has been the problem
Split the circuits and we have solved the issue

6.7.5.2 Industrial type single-phase and three-phase socket-outlets (including
"welding" socket-outlets) shall comply with the requirements of SANS 60309-1
and SANS 60309-2 and, except as allowed in 6.7.5.5 and 7.10.1.6, shall have
earth leakage protection if the circuit is intended to supply portable or
stationary class I appliances.

6.7.5.4 Unless allowed elsewhere in this part of SANS 10142 or for a special
application, the rated earth leakage tripping current (rated residual current) IΔn
required to activate an earth leakage protection device shall not exceed
30 mA. It shall not be possible to desensitize an earth leakage protection
device while the circuit in which it is installed is in service. However, this does
not prevent the use of non-integral earth leakage protection devices when the
rupturing capacity exceeds 2,5 kA.