Do RCCD's work in two phase systems

[Emcneil64]

Hi, I'm a newby hear and wonder if anyone can help me with this question. I work on a ship and our sockets are 2 phase 220volt instead of Live and Neutral 220volt, i.e we do not have a star point at our transformer. Our network voltage is 11KV / 440v Delta / Delta and then transformed down to 440v Delta / 220v Delta wound. Will RCCD's work on this sytem as there is no earthed star point at the supply transformer for the leakage current to return to on the low voltage side of our installation.

 

[Bobster]

IT earthing system? Or center tapped?

 

[Emcneil64]

IT earthing system? Or center tapped?

Hi Rob, cheers for getting back so quickly. I.T. System, no centre tap at the transformer. Our 11kv Generations also has no neutral point, our protection is through an earthed Star point / Open Delta, transformer, which is connected directly onto the 11kv Network, the open Delta winding has resistors connected across which limits any fault current and operates he protection.

On our L.V. We have mostly earth monitoring, although we have some Earth Leakage Circuit Breakers, but we are having a discussion as to whither RCCB's RCBO's etc will work on a 2 phase ships system. Hope this info helps.

 

[Lucien Nunes]

An RCD will function, in the sense that if there is leakage out of the circuit it will trip. It doesn't care where the current leaks to, whether that is earth or the other phase or whatever. However, it might not provide the expected level of protection and may fail to detect faults, depending on how it does or doesn't co-ordinate with the existing leakage monitoring at the supply and the fault current limiting. I think one would need specific knowledge of the system to decide whether they would be applicable.

 

[Emcneil64]

An RCD will function, in the sense that if there is leakage out of the circuit it will trip. It doesn't care where the current leaks to, whether that is earth or the other phase or whatever. However, it might not provide the expected level of protection and may fail to detect faults, depending on how it does or doesn't co-ordinate with the existing leakage monitoring at the supply and the fault current limiting. I think one would need specific knowledge of the system to decide whether they would be applicable.

Hi Lucien, thank you for this reply apologies I got you mixed up with Rob who posted. That's prety much alnong the lines of what we think here, we will get further input from our electrical T?A. But I just wanted to gauge other opinion because as a sea-going vessel our system allows us to run with one earth fault but as the RCCD works on balance I feel it should operate. Many thanks.