Are 44 surge protectors

better than 1?

     But what about surge protectors.  Will 44 surge protectors automatically give your electronic equipment better protection from lightning than 1?  NO they will not, yet the current fad amongst Chinese design engineers and SPD agents is to put one surge protector at every main, branch and local panel--even if a local panel is feeding only a broom closet.

    The reason why surge protection is needed is that electronic equipment will be badly stressed or damaged if subjected to transient overvoltages greater than 1500volts.  One small lightning stroke of 20kA hitting a building with a 5 ohm grounding system could subject equipment to over 100,000 volts--definitely enough to fry the equipment.

   A good SPD can divert most of this damaging surge current away from your electronic equipment thereby protecting it from those high voltage levels. 

     How many stages of cascading SPDs it takes to do this depends on the SPD design and the SPD quality.  For example, SPDs of the spark gap-design have a very high let-through current and let-through voltage.  They always require one or two additional stages of downstream SPDs to clamp overvoltages down to the 1500 volt level--and in many cases they are unable to do it with even 3 stages.  The great number of failed SPD installations using this "3-stage" design is proof of its limitations.

A single MCG Surge Free 160 can clamp a 10kA surge to under 1000 volts. 

    So how many protectors are needed to protect your facility?

     Example.  A 6-floor office building with 6 local panels on each floor.  The all too common approach is to put one SPD at every panel.  The following table shows this.