"Would you care to explain EXACTLY how that will be a problem, provided both electrical installations meet the appropriate standards."

Such installations are installed by professionals who know what they are doing and the associated, possible risks.

I was just issuing a warning to a "possible" non-professional.

Edited by deleted (Tue 16-Jul-13 13:15:39)

Years back they always used to say you couldn't use copper cable between buildings on different electrical supplies - something to do with unbalanced earths? Probably got that completely wrong as not an electrician but I know they always said it shouldn't be done without some sort of way of balancing it.

I believe I have also seen other things since that say this is complete tosh - but I don't have definitive sources for either stance.

Any electricians out there that can confirm/ridicule?

In reply to a post by MHC:

Just look at how many offices have networks? They will be supplied with 3-phase power and different parts of te building will be on different phases.

That was the explanation given as to why my office was connected by fibre to the other block. Electrical isolation.

In reply to a post by ian72:

Years back they always used to say you couldn't use copper cable between buildings on different electrical supplies - something to do with unbalanced earths? Probably got that completely wrong as not an electrician but I know they always said it shouldn't be done without some sort of way of balancing it.

I believe I have also seen other things since that say this is complete tosh - but I don't have definitive sources for either stance.

Any electricians out there that can confirm/ridicule?

On a balanced three phase supply there is theoretically no need for a "earth/neutral". (Look at electricity pylons - they have three main conductors but only one, barely visible, earth/neutral conductor). The currents on the individual phases, vectorially sum to zero.

there's a bigger potential difference between two phases than between one phase and earth - 230V vs 415V approx - that's the origin of the concern. So two "lives" have a big difference in voltage relative to each other if they're fed from different phases.

In reply to a post by yarwell:

there's a bigger potential difference between two phases than between one phase and earth - 230V vs 415V approx - that's the origin of the concern.

Thank you! That is all I intended to convey.

Edited by deleted (Tue 16-Jul-13 13:46:27)

My post was purely meant as a joke (hence the "wink")!

In reply to a post by MHC:

Properly armed a Spitfire could use it's guns to create 100Mbps - by disintegrating Fokkers!

Didn't realise we had Spitfires during WW1! Focke-Wulf (190)?

In reply to a post by XRaySpeX:

In reply to a post by MHC:

Properly armed a Spitfire could use it's guns to create 100Mbps - by disintegrating Fokkers!

Didn't realise we had Spitfires during WW1! Focke-Wulf (190)?

We didn't. But the German Luftwaffe certainly had Fokker aircraft at the outbreak of WW II and then used the Fokker factories to build more aircraft.

But for that to cause a problem you would need an isolation failure at two locations. One failure would cause a problem anywhere. There is no earth connection between the two buildings - Cat5e only carries data signals. and the devices at each end provide isolation.

Go back to to ordinary telephone lines - is there ever a problem running those between buildings? Either adjacent or miles apart? on different phases, different substations ...