Running adjacent ethernet and mains cables?

[Andy Burns]

The magnetics are generally *in* the socket nowadays

[Andy Burns]

Oops, this would help ...

[The Natural Philosopher]

No they are not.

I have wired up DOZENS of CAT5 sockets.

And overseen huge office structured cabling projects.

How on earth do you think that HF transformers are going to cope with e.g. power over Ethernet, or telephone lines, or indeed serial data being sent over structured wiring?

Structured wiring is plain simple point to pint wiring. End of.

I dont know where you got the notion that it was otherwise at all.

[The Natural Philosopher]

That's late 100base or gigabit ethernet only.

Rather a different animal.

[Andy Burns]

The socket on the NIC!

And in the earlier generation NICs, did you ever notice the rather tall DIP packages near the socket, often manufactured by "Bel"?

[tony sayer]

What's that device close to the input socket, opto-coupler perhaps?.

I'm minded to take an old one apart to find out....

[tony sayer]

And the ones where the regs aren't adhered to that well;?...

[Andy Burns]

And before someone figured out they could miniaturise the transformers sufficiently to squeeze them inside the socket, you'd typically see a rather fat IC right next to it, containing them

eg. top left of a 3C905

[The Natural Philosopher]

Ok, I'll take that back. It does seem that micro transformers are part of 802.3 spec.

HOWEVER that is actually a tad irrelevant to the thing we were discussing.

Which was the presence of 230V or whatever on the actual structured wiring. And the chance for an RJ45 plugged into it to give you a nasty shock.

The thinking goes this way.

Low voltage cabling has relaxed standards of conductor accessibility by human flesh.

High voltage cabling goes to extrenme lengths to prevent this. T

Therefore any chance of high voltage appearing on low voltage should be reduced to a vanishingly small value, and earth leakage trips be used as a secondary line of defence.

And as with nuclear, the regulations are ALARA not AHRAS in spirit. The risk is set to as low as reasonably achievable, not to as high as reasonably safe.

It's no great shakes when extruding cable trunking to have an HV and an LV section.

And its quite clear from the fact that gadzillions of done to a price structured cabling setups actually break the rules, that its normally way too onerous.

[jrwalliker]

Well, actually there are isolating transformers on that network card. They are encapsulated in the package marked Bel S558-5999-46. The data sheet can be found on the belfuse.com website.

John

[The Natural Philosopher]

I've already grovelled and admitted that upon research I discovered ethernet 10baset and up DOES have micro transformers in it.. ;-)

But not in the house WIRING.

And I never claimed ever that interference was an issue. Its a safety thing.

HV is HV and LV is LV and never the twain shall meet, is the ideology.

Which can be rather fun in the high power audio where 80VAC is a reasonable voltage level to drive a PA loudspeaker with..representing

1KW into an 8 ohm load..

I've had quite big shocks off loudspeaker terminals.

[Andy Burns]

Well, I think there were two aspects, one that the 230V might zap your kit which the transformers take care of, the other that it might zap someone, for the latter I suppose an 'RJ45' plug offers at best IP30 protection, and not much of a spark-gap, what is it 1Kv/mm?

Yep, plenty of suspended ceilings are a rat's nest of lighting, data phone, PA, alarm cables. Even cable trays that end up carrying hundreds more cables than someone expected when they were fitted back in the day of token ring or coax ethernet.

[The Natural Philosopher]

Indeed. I lifted the floor in a corridor in Telehouse..to lay some CAT 5 to an ISP from our kit.

There had been trunking and trays, long ago, but the amount of wire in there had totally overflowed the capability of the system to accomodate it.

And precious little of it was LSOH either.

However, in a sense, people don't actually work in Telehouse. Only machines.

I think we only made a couple of visits in several years of using it.

[Tim Watts]

Yes there definitely are - in that case they'll be built into the socket:

Something like:

[Tim Watts]

Please see my reply to TNP - they'll be using a jack with inbuilt magnetics. Most do now - but they all will still have transformers one way or another.

[Capitol]

None of my jacks have magnetics in. Whether the source and receiver are transformer coupled I don't know.

[John Rumm]

yup, and quite often opto isolators as well.

[John Rumm]

You can buy sockets with and without still... IIRc there was a delay in the release of the first Raspeberry pi when they realised the wrong socket had been fitted to the initial batch.

[Johny B Good]

Nope! It's still 240v. :-)

[D.M.Chapman]

Yep

We have a recently refurbed datacentre (within 5 years or so) and the room was completely gutted. While power is largely one side, and network the other there is huge amounts of them running together. All cat6.

Given cable management arms on many servers force you to run cables together it clearly isn't an issue :-) Most of our servers have at least 4 UTP, 2 fibre and 2 240V cables bound together in the cable arms.

Darren