yes - what info are you looking for?  Alternatively contact the EOM helpdesk.  They are really responsive

Hi Chris, 

The Helpdesk is really good. The issue is that the source is defined by the substation information, which is normally unavailable or difficult to obtain. I'm trying to get the source to be the origin of the installation, the service head, but it's not easy to input the correct Ze and PFC. 

I was given a workaround by using an unknown source component, but it's not really ideal.

Hi Richard,  do you know the Ze and PSC values but don't know how to enter them?  Or is your issue the fact that you don't have the information and therefore don't know wheat to enter?  

Hi Chris, I have Ze and PEFC and PSCC values. The system I'm working on is TT as well, which isn't a help. But even with TN systems, it's not obvious. The guy from technical help told me to get the transformer values and % and use them...for my next trick I'll nail jelly to the ceiling.

I would set the source type transformer.  I would set it to user defined source and the earthing system to TT and then enter the values in the relevant box:

Unfortunately that doesn't work.

Neither does adding the Ze value as the earth electrode resistance.

I've a Ze of 23.6 and a PSCC of 10.17. 

Hi Richard,

What doesn't work?  Are the values in the data entry tab correct, but the values not being used in the calculation?

That must be an L-N PSSC (assuming kA for the 10.17, i.e. about 20 milliohms round the L~N loop - so close to the TX or a fairly bosky feed cable, )  and an L-E of course for Ze inlcudes the terra-firma path.

All sounds very sensible for a TT installation with decent electrode hence the 20 odd ohms, some at the load end electrode, some at the transformer earthing.

M.

In the images attached, is how you set you a supply for a TT system in ElectricalOM. Ive used the values based on the details in your post

A Earth fault loop impedance of 23.6Ω and a Prospective fault current of 10.17kA

Sorry this should have been a reply to richard64 not chrisbryant