RCD protection for portable equipment with Inverters

[netblindpaul]

OK,
So it's TT.
What is the earthing?
What is the Ra, what is the Zs at the origin of the installation?
What are the Zs's of the circuits?

 

[William Irons]

the earth electrode is 34 ohms and the zs readings are much lower .......parallel paths and structural steel 16 ohms

 

[UKMeterman]

Check which types of RCD are you using, as inverters can have a pulsating and static dc currents in the supply that can upset some RCDs. Ask the manufacture of the inverter for suggestions. Measure the current in the earth if it is excessive you may need to run the inverters off transformers. NB the star point of the secondary will need connecting to the earth terminal of the inverter, this is so the radio intereference filters can work.

 

[Engineer54]

the earth electrode is 34 ohms and the zs readings are much lower .......parallel paths and structural steel 16 ohms

That seems like a high Zs you have there, where bonded building structural steelwork is forming part of your Zs value!!!

 

[netblindpaul]

You have a single earth electrode for a commercial install?