ECN Forum Forums Technical Discussion Electrical Theory and Applications Lightning problem

Surge arresters do work... It's all a matter of quality and upsizing above recommended levels! We are usually struck in this area ( remote valleys all OH utils ) when there is a storm. The results are spectacular on the OH gear but damage to equipment downstream of the SAs is very rare - even comms and modems.

Naturally, it is pointless to put lightning spikes anywhere near util gear - thre surge from strikes fans out from the spike and WILL travel up convenient cables

Spikes should be at least three metres apart and treated much as grounding spikes with the care used to instal them.

To protect IT and comms equ't you DO need smoothing - a good UPS should handle it but again...upsize rather than save $$.


aw... Lost track of yer traffic violations???

Can someone recommend a product that they have installed or seen work.
I would like to get something that protects the load side of the service on, not looking for the little surge protectors you mount for circuits.

I had this very problem at a concrete plant. every time it sprinkled the computers blew on the plant. I started at the service and worked my way thru the buildings. Installed a grounding triad @ the service ( none there), BTW are u sure your rods are 8' and they need to be min 6' apart? Step down transformers were grounded wrong, installed lightning arrestors on each panel and control cabnit.. Not a problem since. that was 5-6 years ago. also installed GEC @ each building ( none before )

I can only assume the lenght of the rods.
One rod is for the electric service and other looks like the phone co put it in. Only 3" apart. Does that matter? Rods for service grounds are 10' I understand, but the phone rod should'nt count?????
What kind of arrestors did you use? How much and where did you get them?

Aryton,

I'm guessing this building has a 120/240 volt 1 Ø service?

Something like the Intermatic EG240RC comes to mind:

Square D and other manufacturers make similar TVSS.

[This message has been edited by ElectricAL (edited 07-13-2004).]

Do those things really work?? I stated earlier in this post that this is not what I wanted. This seems like a "cheap fix" if you can even call it a fix. Is this what u used in the plant u installed arrestors in?
You can buy these at Home Depot, right. I am very skeptical to say the least. I dont want to waste a customers money.

When protecting equipment, a layered or tiered approach yields good results.

The whole service TVSS will have the ability to handle large surges but will start protecting at higher thresholds. The whole service TVSS is valuable for directing the energy under the high spikes to ground, but there is still the energy between nominal service voltage up to the TVSS turnon threshold to worry about.

Therefore, putting more sensitive TVSS units right at the electronics provides additional protection.

The subjective part of all this is determining what is valuable. Obviously the computer and the data stored within is at the top of the list. But, the control chips in the kitchen microwave may have equal value if that's the only way to warm the baby's milk or one has a spiritual need for the morning cup of hot coffee, or the chips in the garage door openner, or the security video recorder.

Once the client lists the most valuable electronic items, one can spec the individual TVSS for each.

For the computers, an additional level of protection can be gained by installing battery standby power systems, providing both TVSS, surge, brown out and blackout protection within the limits of the system.

I was off composing that post and missed your reply.

Yes, IMO, these things work. They are, however, sacrificial. They only can take so many hits and they are dead.

If the service for the building is direct metered, its possible that your PoCo will have a unit that will mount between the meter and the socket.

Units that are wired to the panel, to work at optimum sensitivity, require that the leads be kept as short as possible without bends. Be sure to check out the manufacturers installation instructions. An extra foot of lead not trimmed away will greatly increase the impedance that prevents the surge from getting to the TVSS active elements.

Al

I can remember back in the early Eighties when protecting electronics started spreading down to the individual dwelling.

• The first line of defense was a good ground, some argued that the isolated ground was the key.
• The next line was to install TVSS.
• Next on the list was load specific isolation transformers with primary to secondary Faraday shielding.
• Then standby power supplies of varying response times, the faster, the more expensive.
• Next came full uninterruptable power supplies.
• Then motor generator sets.

I would add two more steps:
1. Totally local power generation with fiberoptic communication (electrically nonconductive) to the outside world.
2. Place the entire stucture with the generation source in #1 inside a hardened mu-shielded encasement.

I'm not trying to be funny or sarcastic. Just making the list.

Noting that your client is cash limited, one must choose what will give the most bang for the buck.

The isolated ground turns out to be a difficult thing to actually get good results from, so it can be ignored.

I would suggest that the first most effective use of money would be for your client to go to the local computer discount store and to purchase a battery backup standby powersupply for the most valuable computer. I would get this before I got TVSS. Be sure to include any phone or cable connecting to this computer.

Next, get a TVSS outlet strip or plugin block with a lot of equipment insurance. . .the higher the insurance dollar amount and the longer the warranty period, the better the hardware will be.

Next, put in the whole service TVSS.

And if you want to spend more money then start working down the list above.

Al

Delta makes an inexpensive TVSS.

The three phase model is listed here: http://www.powerqualityanddrives.com/surge_suppressor_technology/

A similar single phase model is also available for about the same price. Send an e-mail if you want one. I'll arrange to make it available on my web page.

Here's the rule of thumb for direct lightning hits:

I get to keep your money. You get to kiss the equipment good-bye.

Frank