Surge Protection for ac circuits

[working on it]

Recently, one forum member told how his retreat was struck by lightning, and circuits were damaged. Others asked how to protect their trailers from that. I feel the odds of my trailer being struck by lightning are miniscule, but I became concerned about power surges from the park power pedestals. I don't have fuses where the power enters the trailer, but depend on GFCI plugs and power strips. Critical 110vac equipment (the A/C and main fan) have their own fuses (A/C has a circuit breaker in-line), but I really don't know if they will protect after awhile. I read this post http://www.tnttt.com/viewtopic.php?f=30&t=5010&p=51839&hilit=surge+protection#p51839about surge protection failing, without warning. after the protectors age, and that there's no way to tell if the circuit is truly protected. A surge protector that displays its status was recommended. So, after researching, I came up with this Leviton piece

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which has LEDs to indicate status, and a resettable circuit breaker.

• Connects directly to standard NEMA 5-15 wall receptacles
• Diagnostic LED's indicate power & protection status
• Three mode protection for Normal & Common protection: L-N, L-G, N-G
• On-board thermal fusing & overcurrent protection via resettable 15A breaker
• Filtration reduces high frequency noise
• Non-inductive design for compatibility with UPS & SPS or transformer systems
• Multi-component suppression circuitry
• Max. single-pulse transient current (8x20μs, Amps peak): 26kA
• Rated single-pulse transient energy (10x1000μs, Joules): 320 Joules
• EMI/RFI noise rejection @50 Ohms 5kHz-100MHz: 10-20dB
• Cat. A ringwave (6kV, 200A,100kHz): 370V
• Cat. B ringwave (6kV, 500A,100kHz): 420V
• Cat B impulse (6kV, 3kA, 8x20μs): 490
• UL 1449 ratings (8x20μs @ 500A) (L-N/L-G, N-G): 330/500/400
• Maximum continuous operating voltage: 135V

I think it will serve, but I also found higher capacity devices online (if I need better), but for <$15, I wasn't going to pass it by.

[inthewoods]

Looks like a decent option to me. Like you I was a bit concerned with having some surge protection in my TD. I went with a basic super simple single circuit design and have a small 20a breaker at the inlet then a GFCI and then a levition 20a surge suppression receptacle in my galley the other receptacles in my cabin are all inline with the ones in the galley and all protected in one place. It's not the highest grade protection but I figure it's good enough.

Here's a link to what I used:

http://www.leviton.com/OA_HTML/SectionD ... 553C42580D

[Shadow Catcher]

Some protection is better than none. But they do not protect from wiring problems in the pedestal, open neutral (fairly frequent) over or under voltage which can damage attached electronics.
After hearing a number of horror stories I decided to buy a Progressive Industries EMS http://www.progressiveindustries.net
If you decide not to go this route test the source prior to hooking up make up one of these testers. This is found on http://www.myrv.us/electric under the testing

[working on it]

I really bought this surge protector primarily for "surge protection". At my house, we have power surges several times a day (so does the neighbor- we share a "weak" transformer on the main line). I have all my electronic equipment at home on surge protectors, and the windowshakers (I prefer them to the central unit!), each have their own. I have had two surge protectors fail, after several years use, so I wanted one to test that had a status display. Why not use it on the trailer? Surely worth the $15. It will tell me at a glance, if it is good or not. For initial park hook-up, I have a receptacle tester/GFCI tester, 50a to 30a to 20a adapters, and a digital multimeter to check with, also. If I misread something, the new unit will make line status clear to me. The Progressive EMS looks to be a better, quick and reliable way to go, but as I am only interested in running the A/C and or main fan on ac current, if I encounter a problem with the pedestal power (110vac), then I'll check the larger amperage supplies. If all are faulty, then its 12vdc for me. No A/C of course, but the AGM battery can power the main fan (via inverter) for a long, long, time. Then I can recharge the battery before the next evening (even if I have to run the truck for power). And then there's my onboard generator; noisy but, if I have to run it, since it was installed to run the A/C, I will, provided that I can park on the fringe of camp (as usual) to keep from creating a nuisance.

[woodywrkng]

I don't know how the Leviton is built, and it looks like a fine one, but I had a surge arrestor once with status indicators, and discovered that it works by using a small fuse and neon light. When a surge occurred, the fuse blew, the light went out, and the actual surge arrestor (known as an MOV) was now out of the circuit leaving anything plugged into it un-protected. It was admittedly a piece of junk, but having the status indicator made it a one surge device. The MOV should be able to absorb far more than the few amps the fuse was rated at. You can buy the MOVs, they're the size of a nickel more or less, and attach them to the back of any AC socket. When they blow up having done their job, you can certainly tell .

[working on it]

Granted, this unit is not a do-all, nor did I need one (any unprotected device is easy to replace, and cheap; the trailer will be closely watched whenever plugged into parkpower, anyhow...there's always someone nearby at camp). So, for $15, and a coupla hours time installing (using surplus parts from the build, and cleaning up my wire routing for ease of use), I installed a dedicated water-resistant receptacle/plug fed directly from the parkpower input cord, and plugged in the surge protector. Now I have both a surge protector and a GFCI inline before power goes to the next receptacle/plug. I tested everything (including my A/C, which lowered the cabin temp/humidity from 89degrees/55% to 62degrees/38% in a half-hour. I enjoyed the break!).

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[working on it]

(... cleaning up my wire routing for ease of use), I installed a dedicated water-resistant receptacle/plug fed directly from the parkpower input cord, and plugged in the surge protector. Now I have both a surge protector and a GFCI inline before power goes to the next receptacle/plug. ...

Part of the upgrade in wiring was to also remove 110vac power from proximity to water/fuel. Sometimes a water leak from the cooler or elevated water jug might occur, or a fuel leak from tank or generator, as well. Now the main plug connection for park power is elevated off the trailer floor, and all receptacles are now on the upper shelf.

• power block raised off the floor, bolted to wall
• theory of operation

[bdosborn]

Make sure and test the receptacle you're plugging into for ground. The SPD conducts over-voltages to ground through the ground wire so it won't do anything if you don't have a ground.

Bruce

[George Taylor]

I will say that the surge protector outlets do work. Some can be reset, some not. Even so there is nothing that we make that will stop lightning completely. It is still possible for it to "jump" the surge arrestor. Seen in a few times on service calls. They are cheap insurance however.

[working on it]

Make sure and test the receptacle you're plugging into for ground. The SPD conducts over-voltages to ground through the ground wire so it won't do anything if you don't have a ground.

Bruce

My photos of the surge protector as installed show the Power, Protection,& Polarity and Ground all lit. Testing circuits (by operation) was done. So I assumed I had ground! Then, I saw this thread,http://www.tnttt.com/viewtopic.php?f=30&t=60617 about 12vdc grounds (in which I have each circuit grounded directly to the battery, not frame). But what grabbed my attention was the HOT SKIN references, for 120vac. So I thought that I might as well test the circuits for ground as suggested. Though I have always had circuit testers, and receptacle and GFCI testers, and test all the wiring in my house as needed, I never tested my garage circuits with them. I got out my Commercial Electric 3-prong GFCI receptacle tester (which I use to test park power pedestals as well), and went to the garage. I plugged the external shore power line into the wall, which lit up my SPD LEDs as before, this time I tested the next set of trailer receptacles...open ground! So, I tested all receptacles in the garage...all open ground. In the twenty-one years I've lived here, I've never suspected that. I've run many an extension cord over wet ground from there, but fortunately (for me), I used a 12 gauge extension w/GFCI plugged into the garage receptacles first, though I never had a trip or a shock. I guess I could've been the first TnTTT'er to be electrocuted by plugging into shore power...at home. I'll get more GFCI plugs to use in the garage, until I find out where to ground the entire system! And I'll move the trailer's GFCI to first position, prior to the SPD, just in case.

[bdosborn]

Trust but verify I always say.

Bruce

[working on it]

Make sure and test the receptacle you're plugging into for ground. The SPD conducts over-voltages to ground through the ground wire so it won't do anything if you don't have a ground.

Bruce

... And I'll move the trailer's GFCI to first position, prior to the SPD, just in case.

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As promised, it is all I can do at a campsite, short of driving in a ground stake (consensus opinion is negatory on that!)