Surge Protectors etc.

[RJay]

Originally Posted by SCVJeff

Not to morph this into a different subject, but I'm missing the point. What is isolating the jacks going to do other than prevent them from rusting?

When lightning strikes the ground it produces rings called voltage gradients around the point of impact. Visualize what happens when a pebble is dropped in a puddle. The ripples are tighter together where the pebble enters the water and as the ripple extends out from the point of impact the ripples not only decrease in height but they become spaced further apart. The amplitude(height) of the ripple represents voltage. So at the point of a strike the gradients are closer together and the amplitude is the highest, a deadly combination. The more gradients that are bridged the higher the voltage.

Let's say a person is standing 100 feet from a lightning strike with his legs spread three feet apart. Depending on the magnitude of the lightning strike, some are 100,000 volts and 25,000 amps, the rings would be very close together. At 100 feet, each gradient could be in the thousands of volts and across three feet could result in tens of thousands of volts going up on leg and out the other since the body is the path of least resistance.

So if the jacks are down with metal touching the ground, the jacks bridge the voltage gradient and depending on how close the strike is to the RV will determine how much voltage goes up one jack and down the other since the jacks and the chassis is the path of least resistance. So any insulating material you place under the jacks helps prevent the bridge and the voltage entering the RV.

If you are ever in a thunderstorm in an open field, the best thing you could do is to crouch down and place your arms around your lower legs to provide as little height as possible and place your feet as close together as possible, even better, place one foot on top of the other and pray.

[SCVJeff]

I'm aware of the gradient rings. In the 1970's I worked for the department at GTE that produced educational videos for the field guys, including reasons not to drag long ladders on the ground (for all the reasons you mentioned), as well as bunny hop escape routines. I have also seen film of solder dummies getting blown in half when a ladder does strike the ground, as well as what happens to your crotch when you DON'T bunny hop, so I am well aware of what happens. Oh yeah.. I also get to take yearly ISHA/ RSI RF and general industrial electric safety training to further drill this stuff in . In addition, many years ago I had a repeater tower fall across 8kv lines that took out every piece of equipment on the other side of the coax, except that which was sitting on a power supply I made and sprinkled MOV's everyplace I could. Back to the equipment.. When this was over I found pieces of 1/4" rubber mat sitting on concrete that I had a different power supply resting on. That mat had what one might call a laser cut pattern of that power supply right through to the concrete. And this with only 8kv.

Between these 1st hand experiences as well as the many TV transmitter facilities that I watch over around the country and how we deal with both surge and lightning suppression (2 different things), I've seen what lightning and HV in general can and will do. So based on personal experience I stand by the statement that insulating the jack will do nothing unless you want to slide 6+" of DRY dielectric under them.

[sdennislee]

Although some disagreement exists here between the sequence of connections this is one of the most informative threads I have read. Icopied the links offered and will research them and base my configuration on the manufacturers recommendations. Thanks to everyone who took the time to add to this thread.

[RJay]

Jeff,
I wish I knew of your experience before I did all that typing.

The only point to putting something under the jacks depends on the type of material used and the distance the lightning strike is away from the RV. The further away the strike hits the less voltage the RV will see. Soil material also makes a difference, the drier the ground the less the voltage will radiate out away from the strike.

[TechWriter]

Originally Posted by SCVJeff

So based on personal experience I stand by the statement that insulating the jack will do nothing unless you want to slide 6+" of DRY dielectric under them.

While you certainly have experience with HV, I'm going with the advice from Progressive Industries which relates directly to RVs, and not transmitting towers or what do to when you're in an open field.

[NLOVNIT]

We've veered off course. Let's steer it back to the OP's question:

Originally Posted by Piledrive

...The question is, if one is at a park that supplies a defective electrical hook-up, or there is a large spike, does your Insurance cover the loss of TV's, Converters etc., or is this a case of all damage is on the MH owner?..

Thanks.

Lori-

[SCVJeff]

OK, we'll behave.. ):

To the question (and addresses surge protection only), I think this is such a moving target that just because someone were to pop up and say they got something covered doesn't mean the next claim will. That's the problem with a surge, often it can be selective, taking some things out and leaving others intact, and there is no evidence left to file a claim against. Unless you have massive damage where it's clear there was a verifiable event, I doubt any company will step up and cover anything. That's why many look at their Progressive or TRC equipment as an insurance policy (and obviously they do a LOT more than surge protection).

[Piledrive]

Very informative. Thank's to all you guys. If there are any others?

[MONGO MAN]

Originally Posted by Dr4Film

Steve,

Where did you see or read that a Progressive Industries EMS-HW-50C unit needs a Surge Guard to team up with the EMS?

Heck, the EMS-HW-50C unit itself has 3580 Joules of Surge Protection already built into it, one of the highest rated Energy Management System units for the RV industry and I won't leave home without it. I also use the PowerMaster Voltage inline before the PI EMS unit to take care of all low voltage situations around the North American Continent.

Whoever told you that was full of BS.

Dr4Film ----- Richard.

The Powermaster Voltage Booster also has surge protection devices built in(varistors) also the internal autotransformer itself (that boosts the voltage) provides some line filtering & spike protection - I always use both -THE POWER MASTER SHOULD BE CONNECTED AHEAD OF THE PROGRESSIVE IND.UNIT per mfg.