Things to avoid when running RJ45 ethernet cable

s999 · 09-02-2006, 02:31

When you run ethernet cable around the home (for a wired network) then should you avoid electrical wires? I've read somewhere that if you come across electrical wires then you should cross perpendicular to them. And if you want to run parallel to them then you should keep about 6inch distance from them.

What about copper pipes, especially the hot water ones.? Should you avoid them too? Can CAT6 cable run alongside a hot copper pipe?

Any other things to avoid?

mshhal · 09-02-2006, 07:04

Hi S999, if you run your cables parallel to mains cables then you run the risk of coupling in the large transients that occur on the mains when things like fridges/freezers switch off/on. These transients are much larger that the signals on the ethernet cables and will cause the signals to be swamped momentarily, although the ethernet protocol will usually cope with this. In the worst case it is possible that your ethernet ports could be damaged if the parallel run is excessive (many meters). Crossing at rightangles or keeping 6 inches away reduces the coupling to virtually nothing.

Copper pipes should not be an issue unless your electrical wiring is faulty and the only problem with hot water pipes could be damage to the insulation of poor quality cable.

Mike

handyman · 09-02-2006, 09:44

Looking at the costs Cat5 seems to be more expensive than cat6 in many places.
I would look at upping the spec for the cable so that if you move from a 100mbs network to a 1000mbs network you dont have to recable your house

s999 · 09-02-2006, 12:26

What about satellite cable? Can you run this parallel to mains electrical cable or hot copper piping?

If I run the ethernet/satellite cable in some conduit, then would it be ok to run it alongside mains cable?

I want to install one of my ethernet wallplates right next to a plug socket.... so the ethernet wire is gonna come down the wall right next the the plug socket mains wire. I guess I have to keep a 6 inch distance right?

MovedGoalPosts · 09-02-2006, 13:10

I don't see why you have to keep a 6" distance, provided the cables are properly separated in trunking. After all skirting trunking systems used in offices have mutli compartments with power and telephony / ethernet cableing all run within.

mshhal · 09-02-2006, 14:51

S999,

generally in the home, neither ethernet nor satellite cable will run next to mains cabling for a long enough distance to have any effect. If this parallel length is less than a few metres then don't worry about it.

The CE mark on most reputable hubs, routers etc. (in fact any electronic product) indicates, amongst other things, that they have been tested to have a level of immunity to just this effect. (EN61000-4-4 under the EMC Directive if anyone really wants to know!

).

Metal conduit will improve matters, but plastic trunking ijust keeps it tidy.

There is nothing special about a 6 inch spacing, basically 1/2 inch is not very good, 1 inch is better etc.

Rob C

you are correct, that in the office environment there isn't normally an issue , and even if there were, the ethernet protocol means that you would probably be unaware of a problem unless it was so bad as to cause excessive retransmissions and slow the network. It's all a case of best practice, if there is no interfering source then it doesn't matter how badly the wiring installation is, it will still work well. But if it's a noisy environment then you can expect some problems and they can be hard to resolve.