Underground ethernet cables between buildings

[Guest Guest]

I seem to remember reading on here that there are regulations surrounding using copper cables. Am i imagining things or are there? Any advice, links to government sites etc

 

 

The problem is we already have copper cables run between 2 buildings from years ago. 2 out of the 3 have recently failed, one last night. We also had a power cut last night - coincidence?

 

I have no idea what was done when fitting the cables, whether an electrician was consulted etc etc as it was around 6 years ago, well before i started.

 

:beer:

Edited November 12, 2008 by Guest

[White_Fi]

Hi j17sparky,

 

Can I start by asking what you are trying to achieve here? Networking two buildings together?

 

If so have you considered doing this over Wi-Fi?

Ruckus wireless access points use technology called meshing, which literally meshes two or more access points together. I have set this up with a few clients and they love it.

 

However you may be trying to achieve something else, just thought i'd put the thought out there.

 

If you would like to talk more about this you can contact me on 07595718705.

I am on the road but will be in a meeting from 2.30 - 4pm

 

Kind Regards

Stuart

[Guest Guest]

See first post ta. Thanks for the input and we may have to consider wireless if the problem does prove to be underground as id just love to ask the HT for money to dig up the school playground! lol

 

:beer:

[Geoff]

It's buried in the Building Regulations somewhere. I confess I have looked but have been unable to locate the exact section. Basically you are not allowed to connect buildings together with electrically conductive material. This obviously includes Cat6.

[White_Fi]

Sounds great,

 

If you get to do it please post some pictures so we can all have a laugh

 

Rgrds

Stu

[ozzy]

How far are the buildings apart? we have ours connected with fibre optic cable tied to a catenary(30+ metre), also worked out very cheap using pre terminated fibre cables and stringing the catenary is'nt rocket sience.

might give you another angle to look at:rolleyes:

[webman]

The discussion over copper cables being used underground is around the differing ground potential that the buildings could have. What about replacing with fibre?

[Geoff]

Also consider a laser link, microwave or ethernet over power.

[Guest Guest]

Cheers so far people.

 

So geoff, do you think its against regulations then? Not that im doubting you but ive seen quite alot about armored cable specifically for underground applications. Obviously this doesnt mean it has to be inter-building but you are the first person i have found who has said in black and white "it is not allowed". Maybe its a newist regulation?

 

Just dont want to be going to SMT and telling them we need rid of the copper when we dont.

 

 

The discussion over copper cables being used underground is around the differing ground potential that the buildings could have. What about replacing with fibre?

 

In a perfect world id love to. Depending on where things terminate we might actually be lucky to get a fibre pulled through, we'll see. We've actually got most of the equipment already but we have no money. Got spare gbics on the nearest core switch, and we've got a couple of spare switches going. All we'll need is the fibre running and terminating, and 2 fibre modules.

 

Wireless - maybe it will be better now but the reason copper was installed was because too much interfearance was coming from the boiler house to get a stable connection.

Ethernet over power - most likely will have the same problems as above.

[webman]

In a perfect world id love to. Depending on where things terminate we might actually be lucky to get a fibre pulled through, we'll see. We've actually got most of the equipment already but we have no money. Got spare gbics on the nearest core switch, and we've got a couple of spare switches going. All we'll need is the fibre running and terminating, and 2 fibre modules.

 

I understand. If the pipe's big enough you could buy it pre-terminated.

[CyberNerd]

if you already have copper in ducting underground then it should be reasonably easy to tie a length of fibre to the copper wire and use the copper wire to pull the fibre through

[button_ripple]

We have a fibre cable at our school between our two buildings - no problems at all. It was supposed to be installed underground, but the school decided not to do it as it would be too expensive to fix if it broke.

 

We also have a CAT5e cable through a caternary to one of our mobile huts. I don't think that there is anything stopping that?

[Geoff]

So geoff, do you think its against regulations then? Not that im doubting you but ive seen quite alot about armored cable specifically for underground applications. Obviously this doesnt mean it has to be inter-building but you are the first person i have found who has said in black and white "it is not allowed". Maybe its a newist regulation?

 

Building regulations aren't really my area of expertise and are hardly 'concise'. Like I said, I know about this because our LEA pulled us up on it here. We have a science block connected via Ethernet cable.

 

webmans point about ground loops is correct. I've seen the same issue at a nearby primary school. It knocks out their main switch on a regular basis.

[CyberNerd]

We have a fibre cable at our school between our two buildings - no problems at all. It was supposed to be installed underground, but the school decided not to do it as it would be too expensive to fix if it broke.

 

not if you put it in ducting and leave a rope in there. Cheaper than that cherrypicker

[Geoff]

We also have a CAT5e cable through a caternary to one of our mobile huts. I don't think that there is anything stopping that?

 

All external building connections should be non-conducting. eg fibre, wifi, etc.

 

Also with a caternary, you have to watch the height, we can't use them for some building because the section of playground are counted as a 'roadway' for the purposes of getting a fire engine round the site. There's a minimum height requirement (basically about 5m) which is impossible to reach from a single storey building (It's in the Building Regulations and the Highways Act apparently) safely.

[localzuk]

Hmm... How does all this fit in with the fact that all of our fire bell cables that connect huts to the fire system are copper on cateneries. this happens in about 3 places. And was done recently too IIRC.

[jcollings]

not if you put it in ducting and leave a rope in there. Cheaper than that cherrypicker

 

Ah yes but nowhere near as much fun as a cherrypicker

[Disease]

It's buried in the Building Regulations somewhere. I confess I have looked but have been unable to locate the exact section. Basically you are not allowed to connect buildings together with electrically conductive material. This obviously includes Cat6.

 

 

I think you will find that that is totally incorrect Geoff as I have just installed one, I checked with our Local Council for all the regulations and if I needed planning permission and they said it was perfectly fine.

 

I used Armored Cat5e buried 18 inches underground, works a treat.

[Friez]

IMHO your best bet is a switch in the other building connecting to a fibre line that routes back to one of your switches in another building, at least if you want reliability. WiFi to connect two buildings sounds like it could end in tragedy.

 

But then surely the electricity that goes to my house, to the local power station is also physically connected to another building that connects to all the neighboring houses. Hmmmm. Isn't phone line also copper? I don't know!

 

Seems unlikely, but what do I know? I'm no legal expert.

 

At any rate, fibre will give you better bandwidth and reliability than wifi could ever achieve, and while you're at it, string a few through for redundancy measures, to save you digging it all up again.

 

That's the ideal solution if money is no object!

[yabbadabba]

Last time I came across this was when covering CCNA, one of the case studys was a school with extra buildings. For the CCNA it was a no, even though the buildings were under 100m apart. There was no network reason not to use CAT5 etc, I cant remember the reason not too and have always assumed it was either H&S or building regs, not checked it out though. Might send my nice man at the council an email to confirm though as we have 1 x external building thats joined with CAT5.

[SYNACK]

But then surely the electricity that goes to my house, to the local power station is also physically connected to another building that connects to all the neighboring houses. Hmmmm. Isn't phone line also copper? I don't know!

 

Seems unlikely, but what do I know? I'm no legal expert.

 

The phone system has its own closed loop power system which will not ground out making this a safe setup.

 

It is perfectly possible to mave copper between the buildings but it is asking for trouble if the buildings do not have a common earth. Ethernet cable can already have a potential difference of around 40V with a standard setup if you have copper links between two seporatly grounded building these can get much higher. This runs the risk of in the short term tripping out the switches making them unstable or long term burning out the ports/cable if there is enough discharge through them.

 

The bell system is also likely to run on its own DC closed loop system removing the grounding problem, the gague of the cable used is also much higher so extra charge is less likely to cause damage.

 

The main reason to use fiber is to electrically isolate the equipment. This can limit damage in the case of lightning strikes or power anomilies. It is also less error prone.

 

If you have the conduit already there get them to use the busted copper links as a pull through for a fibre. Wireless is really a second best solution which is only usually considered if laying fibre is to expencive because of digging. In the long run fibre is much more robust and much more expandable as a single mode pair can easily carry 1,10 or even 147gbits/s worth of traffic as apposed to spending vast ammounts to get a link that actually runs at a stable 1gbs/s wirelessly.

[john]

Sounds great,

 

If you get to do it please post some pictures so we can all have a laugh

 

Rgrds

Stu

Keep your eyes peeled when you are in your 2:30 - 4 meeting tomorrow around the campus and though shalt find some excitment if that stuff floats your boat Certainly doesn't float mine I want rid of it and are working on it but things take time and planning

[SpuffMonkey]

We have a fibre cable at our school between our two buildings - no problems at all. It was supposed to be installed underground, but the school decided not to do it as it would be too expensive to fix if it broke.

 

Another vote for fibre here - though we did have a couple of problems -

 

When we had diggers on site doing some building work - one caught the buried line and just kept lifting - its quite amazing how far it stretched before it snapped it pulled all the fitments off the wall 50m away where the cable ran up the inside of a wall too!

 

Later the kids dug it up and cut it with some shears - which was a pain to have repaired!

 

Apart from that - top notch!

[TYO]

we are looking at commising two underground fibres, anyone got any recommendations on who to use? or who not to?

[YorkshireTechie]

i started a thread on this very subject a few months ago and got back some very different opinions.

 

since then iv had the schools electrician involved and the LEA fire officer and i have been told its fine to put in external grade cat 6 in some conduit underground to connect the two buildings together, we are going to use a trench that is being dug by the fire alarm company that is also connecting the existing fire alarm to the other building.

 

now im not saying that im right and other people are wrong its just that there does seem to be alot of differing opinions on this matter.

 

to be honest id love to get this one clarified once and for all.