Ethernet cables near power cables

bcjames

bcjames

bcjames

Soldato
Joined
7 Jun 2003
Posts
6,234
Location
Leicestershire
Hi,

We live in a typical victorian terrace with a 'tunnel' entry to access the rear garden. This is a good size space, about 1.5m wide and 12m long, so has various services stuffed in to it, as well as some newly fitted lights for when I get my motorbike in and out.

s5xTMw6l.jpg

My study is in the room directly above the tunnel, and has the router etc. My plan was to drop (in addition to the other access points that are routed via the attic) two cables out of the study (starting just off camera to the right) and along the wall shown, right at the top. One would enter the front room about half way down the wall, and the other would run the full length of the wall, popping out the other end to provide an external access point. The trouble now is that puts them very close to the lighting wiring.

I've got 100m of external cat5 with which to complete the project.

The lighting is spurred from a plug socket. The top cable is the two way switching, and the bottom cable goes to the lights.

I think I've got a couple of options, but would appreciate some further input.

  • Move the lighting wiring down, giving about a foot between power and data.
  • Run data on the other side of the tunnel, and cross it back over the ceiling where it enters the front room.
Non options are:
  • Running the cable internally (the floorboards are a nightmare to get up safely, and the joists go the wrong way).
  • Shielded cable (cost prohibitive).

How much gap should I have between the two?
If I go across the ceiling, will it be okay to cross the power cables at 90°?

Thanks for your help.

James
 
I'd be surprised if there was an issue with your initial plan - having seen the state of some of our trunking at work done by "professional" installers (with Cat5 and mains cables incorrectly in the same sections, or going through walls in the same places - and all working fine), then I think the "risk" is generally overrated.

EDIT:
It's normally industrial equipment, e.g. Motors and the like that generate noticeable interference, and need consideration taking with regards to cabling
 
Last edited:
You'll be fine with that, even the mains cables that go to your meter are shielded well enough that you could run Ethernet cable next to it.
 
Thanks everyone, very reassuring! It would be a bit of a pain to do it any other way, so I'm glad the plan will work out.

I haven't measured yet, but given the depth of the coving in the front room, it's likely the cable hole for the cable going to the access point will be below where the lighting wires are run. Can I just cross straight over the power cable at 90 degrees, or is there any other consideration I need to make?
 
If you’re crossing a mains cable you are supposed to do it a 90 degrees.

You are really worrying about something that won’t be an issue. Ethernet is very forgiving.
 
As @Armageus indicates, you'll be fine unless you've got something that pulls a lot of current or generates a large magnetic field. (It was an aircraft maintenance hangar in my case.)
 
Non issue. I have cat cable directly in line with power for meters outside my house and zero issues.

I would love to see hard evidence of any interference apart from just the usual internet bs from armchair electricians.
 
You won't have an issue at all. I would put the data cabling in some galv conduit though, especially for the cable going back into the wall halfway down. You don't want to have to redo it because someone drags something past and damages it.
 
Given the choice between possible damage to a cable and having galvanised conduit attached to the wall I think I'd take the risk.

From the description the cable would be coming out at shoulder level or above anyway.
 
Our ceilings are approx 8-9 ft high, so a run out of the first floor and in to the ground floor at frieze all happens a couple of feet above head height.

It's a good point though. There is an ankle level gas pipe running down the same wall, which always feels a bit vulnerable!
 
It does make me laugh when people suggest 'just put it in a bit of galv conduit' Not many people are going to have the tools (or skills) to install galv conduit correctly, and as a result would likely look rough or the unfinished ends would damage the cables.
 
I'm sure people are capable of reading suggestions and deciding for themselves whether it's something they are capable of doing, or consider to be worth the effort. The alternative is to arbitrarily decide not to post certain things based on an assumed level of skill of other posters.
 
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