David_Wallis

no but.... wiring regulations and all that bollocks saying that all earths should be bonded together and this would mean that you can get a shock between earths... hence why you bond pipes in your house...

edited to say that I wasn't thinking of the fact that the hubs and switches are isolated... it just that you shouldnt bring another earth into the house... so the rj45 cable could be like a live wire should you be touching the wrong thing at the wrong time.

David

[Edited by David_Wallis - 4/3/2002 9:10:40 AM]

Carl Harvey

I'm just having a network installed into a new house.

There will be a small 10/100 cat5e network in the house and another in the office above the garage. Both will have a 5 port 10/100 switch in.

I had planned to join both networks with the cat5e cable in trunking under ground, the problem is that the garage and the house are approximately 20m apart.

I have been advised that I must use fibre to join the buildings.

Is this really necessary as it is fairly expensive.

David_Wallis

Not really if its at home and they are on the same mains supply... Make sure you run the cable through suitable conduit, Ideally use stp instead of utp..

Regards

David

[Edited by David_Wallis - 4/2/2002 8:43:15 PM]

[Edited by David_Wallis - 4/2/2002 8:45:50 PM]

NickAdams

iTrader: (5)

David,
I assume you mean STP?
Runnin RJ45 cabling in a house is not a problem.You only hit problems when you start hitting the limitations of copper cabling ie 100 metres although it's more for STP anyway!
Go for it!

Nick..

David_Wallis

Thats what I said...

for some reason I put that because I foil on the brain...

Dumb as$...

I know what I meant anyway!!

David

ChrisB

You could stick in lighting arrestors for extra protection at each end but they aren't cheap last time I looked.

Belf

The only thing that may cause a problem is if the two houses are on different mains phases as they will then no longer share a common neutral. If so then you will need to gets some optical isolators.

AndyC_772

iTrader: (2)

Ethernet interfaces are usually isolated to 2kV anyway. As long as the cable is buried, you don't have anything to worry about.

The only potential safety issue is if the cable running between the two buildings is exposed and could be struck by lightning, then you'd need to install a surge arrestor. If it's buried, though, then there's no problem. You should run the cable in a separate conduit to any mains cables for added safety, just in case someone ever puts a spade through the conduit and shorts them together.

There's no issue at all with both ends being on different mains phases, which I doubt they are anyway - Ethernet is always isolated from the mains, and your switches almost certainly will have isolating power supplies too.

The cable length limit for 100 Mbit Ethernet over cat 5 utp is 100 metres - this is a technical limitation and nothing to do with safety.

Andy.

Jeff Wiltshire

The two buildings should share a common earth or you could have different voltages either end....

Also make sure you put the cable deep if your using copper or when the ground freezes you may find that you lose the connection.


Jeff

AndyC_772

iTrader: (2)

Sorry, Jeff - it doesn't make the slightest difference if there's a difference in Earth potential between the buildings. Ethernet uses transformer isolated differential signalling, so no conductors are ever connected to Earth. The line is completely isolated at both ends.

Disclaimer: I'm an electronic engineer working for a major manufacturer of data networking equipment

Andy.