dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
1121
share rss forum feed


viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA

3 edits

OFF TOPIC magetic inteference on cableing / switches

Picked up a job to rewire a medical office. They are into imaging. The telco/ switch room is in the same room as some HUGE ASS helium cooled ( I think from what I was told) giant electro magnet thing??

When the imaging is going on the latency across the network goes from less than 1 ms to upwards of 4000-5000ms when these electro magnets are energized.

They have multiple switches around the other offices that all aggragate to this one room. We are tasked with getting rid of all switches in other locations and centralize into this one room. Any thoughts of how to prevent this latency spike?

I thought of running shielded cat 6 or cat 5 but not sure if this will fix the issue with the noise or magnitisim getting in to the switch or thru the cabeling. Cant really test with pulling cables off line or switches during the day and I sure as hell dont want to try and turn this thing on after hours and risk damaging something.

Anyone ever run into this? I was also thinking of using shielded patch panels.

Thoughts and or suggestions are much appreciated.

--
»www.accelwireless.com
ComTrain Certified Tower Climber.
Wireless and IT consultant.
Proficient in Mikrotik


LLigetfa

join:2006-05-15
Fort Frances, ON
kudos:1

Ja, I believe it. I was called in to solve an intermittent problem for the PoCo that occupied three floors of a high-rise building. Three or four times a day, the network would flake out. It was always first thing in the morning, noon, 1:00 PM and quitting time. Everyone thought it was related to just higher usage at those times but I proved that to not be the case.

Turned out they had CAT5 cable runs going through the elevator shaft and they ran the network cables too near to the power cable for the elevator. Whenever the elevator had a full load, the motor drew more power and induced a larger magnetic field. I could feel the current flow simply by grabbing onto the insulated power cable just like one can feel it grabbing the cable on an arc welder in use.
--
Strange as it seems, no amount of learning can cure stupidity, and formal education positively fortifies it. -- Stephen Vizinczey


Newbie

join:2011-04-18
reply to viperm

This is probably completely OT as it was a different problem, but I had some wireless gear on an FM tower that I was having tons of problems with Ethernet negotiations.

When I switched the cabling out fro ToughCable Lvl1 to Lvl2 the problem went away completely.

If I was going to re-run cable, I would get shielded cable like you are thinking and even cable with the cross-talk divider as that seemed to make all the difference in my case.



viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA
reply to viperm

But what about the actual switch itself will any switch be okay to use as long all cable runs, patch cables and patch panels are if the shielded variety. Do I need to spec a specialized switch?



TomS_
Git-r-done
Premium,MVM
join:2002-07-19
London, UK
kudos:5
reply to viperm

Faraday cage?

I guess it does depend on whether this is interference induced into the cables, or the circuitry of the routers/switches themselves.

Perhaps you need to make some temporary runs of shielded cable along side the existing runs to some users that are experiencing issues, and see if they experience the same kind of issues. If you cant re-produce it, then perhaps its just as simple as replacing all of the cabling. If it remains, you've got bigger problems.

It might be worth recommending a move away from this room due to the issues being experienced, rather than concentrating more stuff in it.



viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA

I agree gonna talk to the IT manager, my friend and see if we can try his first I really don't want to pull all new cables only to find out its the Switch. Then again we have to pull all new cable to most locations... They have lead blankets for the techs there, was going to suggest to him to take a lead schmock and throw it over the switch to see if it makes any difference.



WHT

join:2010-03-26
Rosston, TX
kudos:5
reply to viperm

said by viperm:

We are tasked with getting rid of all switches in other locations and centralize into this one room.

Sounds like the "retasker" decision person bit off more than they could chew. Try to talk them into a different room.


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:6

1 recommendation

reply to viperm

Shielding in cable only affects the electric field, not the magnetic field.

Also, a Faraday cage would prove ineffective as well.



viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA

1 edit
reply to WHT

Ha ha not really just helping a Friend out as well as getting paid to do it. He just got hired as the IT manager I suggested the same thing but locations are limited....



John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:6

said by viperm:

I suggested the same thing but locations are limited....

Distance is the only (practical) solution.

I've built this kind of facility before. All of the gear not directly related to the imager was located as far as possible from the machine as we could get it.


WHT

join:2010-03-26
Rosston, TX
kudos:5
reply to viperm

said by viperm:

locations are limited....

Change location, put up with crappy service...Pick one.

voxframe

join:2010-08-02
reply to viperm

What he ^^ said.

You have NO option in this room.

Either the equipment moves, or they can stuff it and suffer.

There is no viable way to fix what you're dealing with, and most certainly not at the energy you're dealing with. (Look those things up and you'll soon see there's no messing with them).

Anything you do in there will be a cobbled band-aid solution that either won't work, or will work like shit.

You need to drill it into the client's head that the equipment being in there simply can't happen if they want the results they expect. Either the networking stuff moves, or the magnet moves. lol



viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA

My buddy says they are the "power supplies" for the imaging machines not the electro magnetic part of it, not sure if it makes any difference.

Several of their offices are like this. I will be looking at a local office tomorrow evening to see the layout myself and run some tests. Shielded and non shielded cable into the room and around the room to another location if possible to get the best results.

What we do tomorrow will dictate what we can expect at other offices.

I have already speced out shielded patch cables, panels and cable.

--
»www.accelwireless.com
ComTrain Certified Tower Climber.
Wireless and IT consultant.
Proficient in Mikrotik



John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:6

Helpful hint: don't have any ferrous tools in your pockets around the machine when it's operating...


lcnoble

join:2006-11-11
Nancy, KY
reply to viperm

Viperm, it appears that you are involving yourself with Magnetic Resonance Imaging. Thoroughly educate yourself, (the basics are really not that complicated), before you jump into this project. The age and strength of the magnet determines the Gauss line at distances measured from the magnet. I assume that these days the magnets are very shielded and the strength of the field does not extend very far from the magnet. Exposing a conductor to a changing magnetic field induces a current in that conductor. Do not forget that magnets attract metallic objects. I am surprised that your were not briefed on magnet safety. Most conductors entering the magnet room usually must pass through a wave guide to eliminate frequencies detrimental to image acquisition.

In the early days I saw people wrestle with unattached pipes in the area of the magnets. I also saw a carpenter loose all of the nails in his pull behind wagon because he did not heed posted warning signs. Do not be responsible for quenching the magnet, if that is still possible!



viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA

I know about electro magnets... I am and was not even going to walk into the room while it was functioning....

Thanks for all the input..



John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:6
reply to viperm

»www.willis.com/documents/publica···9_V6.pdf


gunther_01
Premium
join:2004-03-29
Saybrook, IL
reply to viperm

Pull fiber instead?


OHSrob

join:2011-06-08
reply to viperm

Delco Wire makes a STP wire (it has a solid aluminum shield that is about 1/16's of an inch) when coupled with a proper grounded rack with emi shielding and proper grounding techniques should minimize the effects of this as low as you can.

That said its not cheep its at least $0.80 per foot.

That said as others have told you its a better idea to just relocate this, This is a bad room for that and you will never fully stop the effects of this device.


spectrumhead

join:2009-05-03
reply to viperm

What gunther said above. Pull fiber. Thats it.


voxframe

join:2010-08-02
reply to viperm

Just ain't getting it...

I've been in these rooms.

STP, whatever, isn't going to help. There's nothing you can do to shield yourself from these.

Pull fiber is one option, but from the sounds of it you have other equipment in there. Switches, routers, etc will also be susceptible to "issues" from these things.

As was suggested above, read up on these things and you'll start to understand just how much of a corner you are in. I understand you're not directly IN the imaging rooms, that doesn't really matter. Not only are the imaging rooms dangerous in their own magnetic way (Carrying tools)... But the equipment in the back room that powers these monsters are nearly unfathomably powerful.

Do every kind of voodoo dance and shielding you want, and again as I stated, it won't help, or it's the equivalent of bubblegum and duct-tape. Get out of the room, or run ONLY fiber in there. ONE SINGLE COPPER ANYTHING (In a cable or a box) and you're right back to square one.

EDIT - For the price tag of these things, and the knowledge required to have/run them... Your client had better be able to get it through their thick heads that networking equipment can't coexist with them. If you're client is throwing a stink that they don't want the networking stuff to move, then DROP them. You're only going to create headaches for yourself by trying to make this work.



viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA

2 edits

1 recommendation

reply to viperm

Click for full size
Click for full size
Click for full size
Click for full size
Click for full size
Click for full size
Click for full size
Click for full size
Went to one site tonight and the network equipment is in a rack about 5 -10 feet away from all the transformers for the Toshiba imaging systems.

Turns out the latency is not bad. The latency goes from about 2-3ms to about 45-50ms out to places like google, yahoo etc.

Most of the issues I think are going to be outdated switches ( old 3 com units) Mix match of off the shelf linksys gear.

We will be home running cables and adding some managed switches to control more of the network. Well the IT person will be able to manage it.

The last IT person has several managed switches that they are "not managing" because he never configured them with any IP's so they have default ones and who knows if there are IP conflicts going on etc.

This place is a mess the IT person before was more interested in taking care of websites and taking pictures of cute women to put up.

Asked the office manager about 24x7 support for their Sonic wall routers we will be supplying. She asked why 24x7 support we are only open 9-5pm??? I said "because you dont want to work on your network during normal business hours"---- LIGHT BULB!!

She said OHHH that makes total sense!

Why did the last IT person not suggest that she asked. I just said I dont know but your new IT guy is on the BALL!

MY buddy asked the outgoing IT guy where all the passwords are for everything. He says uhhh I have them my buddy asked again where? the outgoing IT guy says "in my head I will write them down...

Just walking into one office so far I will have plenty work for the next few months replacing switches, patch panels, adding cable, and replacing UPS batteries.

Instead of replacing the bad battery this guy would just ignore the big red light that said "REPLACE BATTERY" Really I dont see what this guy did and got paid to do? Oh well not my issue all I know is we have work to do..

FYI When I arrived on-site, the shielded doors to the units with all the BIG power wires and cables going to them were not even shut just wide open. Gee I wonder if that has anything to do with issues in and around the network equipment..

No one seems to know where the keys are to lock them up so they stay locked except for maintenance.
--
»www.accelwireless.com
ComTrain Certified Tower Climber.
Wireless and IT consultant.
Proficient in Mikrotik

OHSrob

join:2011-06-08
reply to viperm

In my opinion I do not feel that rack is sufficient to blocking EMI from that imaging device.

I would check the used market for one with a front and rear door as well as sides.

I would imagine the seek time is all over the place on your storage array when that device is in operation.

Also is your rack and switch grounded with a dedicated ground ?



viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA

I saw no grounds anywhere on that rack that was something I brought up as well. RIght now they just want to update the switches and patch panels everything else in due time..


voxframe

join:2010-08-02
reply to viperm

LOL What scares me more is that rack in the middle of a (I'm assuming) high traffic closet, right next to cleaning chemicals and a big-ass transformer system with the cabinets wide open. These guys seriously don't have priorities in order... This is a clinic/hospical/medical center right?

The last IT guy should have been shot.



viperm
Carpe Diem
Premium
join:2002-07-09
Winchester, CA

You are correct!!! THis guy was doing stuff in the middle of the day to he staff pc's they would call and he would ignore them. They would wonder why he was rebooting wihout telling them etc it was a mess till my friend got in there.


LLigetfa

join:2006-05-15
Fort Frances, ON
kudos:1
reply to voxframe

said by voxframe:

LOL What scares me more is that rack in the middle of a (I'm assuming) high traffic closet, right next to cleaning chemicals...

That tells me that access is not controlled to HIPAA standards. I only have to meet SOX standards and could not have a setup like that.
--
Strange as it seems, no amount of learning can cure stupidity, and formal education positively fortifies it. -- Stephen Vizinczey


Jerm

join:2000-04-10
Richland, WA
kudos:2
reply to viperm

I big time LOL'd at this. We almost had the same "kind" of problem at my work.

Fortunately the building is already 100% fiber to the desktop:

»www.flickr.com/photos/emsl/4331026822/
»www.flickr.com/photos/emsl/4330292997/


LLigetfa

join:2006-05-15
Fort Frances, ON
kudos:1

said by Jerm:

Fortunately the building is already 100% fiber to the desktop:

I was doing network design work for some generating stations for the PoCo a couple decades ago and when I proposed fiber, they turned it down saying that it clouds under nuclear exposure. Mind you they were all coal fired. They wanted me to design with 10BROAD36 instead.
--
Strange as it seems, no amount of learning can cure stupidity, and formal education positively fortifies it. -- Stephen Vizinczey

OHSrob

join:2011-06-08
reply to viperm

Click for full size
corenetwork rack
Try to see if you can find a rack like this. With solid metal panel's and a honeycomb style mesh on the door's.

Also before someone else chimes in about that florescent light not being 1 meter away from my cat6 as per cisco guidelines. I have since relocated the light it.

We have the Rack grounded with 4AWG to the panel's buildings electrical ground as per the instructions. The grounding lug's on the switch's/routers have 6AWG running to the grounding plate in the rack.