Lightening vs. the home automation sytem= lighting wins?

[E2BRUCE]

I have a home that I wired a few years ago which due to its location acttracts lighting strikes. This house has a very costly lighting control system that is especially sensitive to surge. I will be installing primary and secondary whole house surge supressors on each load center, but I was wondering if anyone had a suggestion for protecting the individule 120v circuit supplying the main processor for the home's automation system. I would prefer not to use a receptical type surge supressor for fear that it may get unplugged and thus taking the entire homes lighting out with it. Are there any hardwired single load solutions available for protecting this co$tly processor?

 

[hurk27]

Protecting against lightning is more then just installing TVSS equipment, allot of it has to do with how you run your conductors in the structure, and how the different systems enter the house from outside, it can be very costly and add many hours to wiring a house or business, first having all you systems like cable, phone, and power enter at one point is a start, building a ground ring for them to enter through is even better, also how you run run you conductors and the paths they take inside can make a difference on near field strikes, running home runs together till the point they go to their respective devices can cut down on multi-paths that can act like a transformer winding with near field strikes, oh and TVSS don't protect against near field strikes.

The idea is to group your power and signal pathways so they act as one conductor when in the field of a lightning strike, as we know current can not flow on just one conductor, the worst installs I have seen was where you have an entertainment system on one side of a room plugged into one circuit and a sub amp on the other side of the room plugged into another circuit that takes a whole different path back to the panel, with the audio cable inbetween, this allows a loop that the near field strike can set up eddy currents into these paths putting a high voltage potential between the sub amp and the entertainment equipment which can result in destroying the sub amp, and or the I/O board in the entertainment system, also I have seen where the audio cables running between them are vaporized, but since this would be impossible to do after a house is done being wired, the best you can hope for is to install TVSS at both the main panel and the load end, and not just one circuit, having a few TVSS units around the house can act together to build up a more robust protection over all, by making sure you have at least a couple on each phase of the service, having TVSS at the load end is important as lightning and or transients are high frequency events, and impedance of conductors can be very high which does not allow the TVSS to protect very far down a circuit, so this is why having protection at the panel and load end is important.

 

[Jacob S]

Check these out: SurgeX http://www.surgex.com/products/sx20ne.html. Single 20 amp junction box style protector. Look into surgeX...they are well respected.

 

[Speedskater]

While SurgeX and it's copy-cat "series-mode" surge suppressors are all rather expensive, they do an excellent job of branch circuit protection.

Jim Brown the AES committee chair on EMI/RFI wrote a great paper for New Frontier Electronics (the SurgeX people). Of the papers 41 pages, only one is about SurgeX equipment.

http://www.audiosystemsgroup.com/SurgeXPowerGround.pdf

 

[gar]

110201-1008 EST

E2BRUCE:

hurk27 had very good suggestions for you. The magnitude of an induced current into a loop will be a function of the number magnetic flux lines that couple into the loop.

You minimize this coupling by making the cross-sectional area for the loop as small as possible. So instead of running two wires that constitute a loop far apart you make these as close as possible. Further you twist the two wires together. This is called a twisted wire pair. In a twisted wire pair you have many small loops that because of the alternation the voltage induced in one loop cancels the voltage induced into the adjacent loop. This is based on the assumption that magnetic field is fairly uniform in intensity over many of the little loops.

To protect your main power supply and processor you can consider a Sola constant voltage transformer (ferroresonant device). At its input you also probably place a transient voltage limiter.

There should be only one earth grounding point at the entrance to the house. There should be no other connections to earth within the house. You do not want lightning current to enter the house and flow thru the house to some internal grounding point.

As hurk27 said all wires and conductors (electrical, transmitters, water lines, gas lines, etc.) should enter the house thru a single location. Ideally there would be a large copper plate as a bulkhead at this point that is grounded thru a wide flat conductor, and has shunt filter capacitors, and series chokes on each of these conductors.

.

 

[ELA]

What type of Home automation is it?

What type of Home automation is it?

How does the home automation system communicate with devices that are part of the system?

That may help decide what type of protection is warranted.

I recently installed a Leviton 5280 Surge protector receptacle for an LCD. I did not want a wart or Surgestrip hanging out of the outlet and this in-box device was handy. Not the best level of protection but something.