Ok to use additional surge protector?

[Andrew Shoen]

I was talking with a guy who has a built in surge protector (as mine does). I noticed he also was using a surge protector at the power box then plugging his coach (with built in surge protector) into it.

He said it is added protection if the built in goes out. I never thought of it but thought I would ask you as you have been doing this much longer and know right from wrong.

Is that bad or will not hurt anything?

Thanks and safe travels.

[Jim Edwards]

No It will not hurt. The protection is additive so a 10,000 joule plus a 20,000 joule would give you a 30,000 joule protection. I should be noted many surge protectors are a consumable. As they see spikes, they sacrifice components in themselves to protect the circuit. that is why they often have indicator lights to show that they still are offering protection. So I might argue it is a good idea to add another. I have two myself. One in the transfer switch and one in a hard wired autoformer. The autoformer selectively boosts voltage  bases on input voltage for those pesky old campgrounds.

[Fred Brooks]

    Andrew, that is a good question and I am not really sure. I do know that almost all plug-in surge protectors al sacrificial by nature and absorb the hit if there is a surge or lightning strike. Cheap insurance to protect all the electronics in your coach. Fred

[Jerry Emert]

Yes I use two also.  I went to a seminar given by a pretty popular RV Electrical "expert."  He said the same as Jim said above.  Hopefully spikes will eat the cheaper of the two at the pedestal before it gets the installed one.

[Mike Shumack]

Does anyone use the Hughes AutoFormer? https://hughesautoformers.com/voltage-boosters/

There was a thread about a movement to ban this device in the 2020 NFPA electrical code because it causes additional loading on the campsite electrical grid - however that would only be the case if the campsite is providing low voltages to the pedestal. In the case this device boosts the voltage back to where it should be (which protects your Coach electrical system/devices). It's not cheap - but it seems to me that protecting your coach against low voltage is equally important as protection against spikes and surges.

What do you think?

[Steve Huber Co-Admin]

Mike,
A ~$300 50A Surge Guard will trip if incoming voltage drops to 102. To pay more than double that for added protection seems a bit much. In 15 years of RVing with a coach, I've never run into a low voltage situation at a park, to my knowledge. Also, having a device that raises voltage for yourself at the expanse of  the other reisdents doesn't sit right with me. Just my  opinion.
Steve

[David T. Richelderfer]

Paying good money to an RV park for FHUs that doesn't provide at least 115v to each and every pedestal at all times doesn't sit right with me.  Somebody, someway needs to alert the RV park of their insufficient power supply.  And I suppose a good way to alert the RV park of insufficient power is for several customers to complain.

[William Jordan]

Not the original question but Hughes disputes the claim it takes others power. I’m no electrician but my understanding is if you have (to keep it simple )a 30 amp coach and voltage drops it “steals” Your  amps to increase volts. So drawing the 30 amps your paying for nets the only enough to power , say 25 amps of stuff but at a higher safe voltage.  Sure your still drawing the max 30 amps from the pedestal but powering less equipment. Your not stealing your neighbors power. I’d rather than do that than slowly burn up my a/c compressor on 104 volts. Or be without power at all.

[Gerald Farris]

The theory that Hughes uses to "prove" their point that the Autoformer does not use more power is that an induction motor like the A/C compressor will use more amps as well as overheat if it is operating on lower voltage current. So increasing the voltage will lower the amp draw enough to offset the increased draw of the Autoformer. However, the theory does not hold true with a resistance load like the AquaHot electric element or the 120 volt circuit for an absorption refrigerator. Therefore, their theory is only partially correct at best. That being said I have a hard wired Autoformer in my coach because I have encountered low voltage at several older membership campgrounds, especially the ones with aluminum wiring.

Gerald

[Jim Edwards]

Hi, To hopefully add some clarity. Power is measured in watts and is defined as voltage times current. So 12.5 amps at 100v is 125 watts. 10 amps at 125 volts is also 125 watts. For a given motor load, lower voltage would need a higher current. A higher current would create more heat and be more taxing on coils, relays and contacts. This is why wire gages are rated for current not power. Wires also have a voltage rating but this is related to the electrical insulation to prevent arcing and a temperature rating so the insulation does not fail.  Low voltage can do odd things to electronics as well but it is more related to the design of the specific device as to weather it is a issue or not. The problem is you cant really tell until it blows up!
There are other factors at play here and by no means is this a comprehensive explanation but it will due for the autoformer discussion.

As for steeling power, one must remember the limit for power is at the post. It trips at whatever voltage it is at, hopefully, at its rated current. The autoformer is after the fact so you are NOT taking more than your fair share. An example would be voltage is 100v on a 30 amp breaker on the pole. You get 3000 watts. You plug your autoformer in and it takes you to 120 volts. You get 25 amps at he coach before the breaker on the pole trips. You Don't get 30 amps at 125 volts, you get your same 3000 watts. Another way of looking at it is to get your 120v at 25 amp at the coach you are feeding the autoformer  100v at 30 amps at the pole. (voltage and amps chosen to make math easier!!)

And yes I have a Hugh's autoformer with surge protection and it has come in handy in older parks that are farther out on the grid, especially in Canada and Alaska. Stuff works the way it should where others in the group without had issues. If you know the power is good where you are going you don't need one. I just never know.

[Jerry Emert]

With mu limited expertise in electricity I would guess that if the autoformer pulled more than your 30 amp or 50 amp allotment of current the breaker on the pedestal would blow! So not sure how it could rob other campers.

[Andrew Shoen]

So after reading your posts I went outside, shut off power, plugged surge protector into box, plugged my power cord into surge protector, and turned on the power. The surge protector was getting power, but not the coach. I turned off power, unplugged shore power from surge protector, plugged shore power back into power box, and turned on power.  Coach gets power without added surge protector, but will not power up when the additional surge protector is plugged into power box.

This happened the first time I tried to plug a surge protector into the power box, so I just have been running with the built in surge protector, but thought I would ask the group and try again.

I am having some other electrical issues on the coach (Magnum charger, solar power, and some other things) and just curious if those "issues" are what is not allowing for the additional surge protector, or it is something else.

Thanks.

[Mike Shumack]

It sounds like the "additional Surge Protector" is blown.

[Andrew Shoen]

Really? Brand new and all lights power on, says its working.

[Fred Brooks]

    Andrew, Sounds like you have figured it out already. I believe you have a defective "plug in surge protector" If you take it out of the loop and you have both legs of 120 volts coming into the coach, that is your issue.
  By the way, the correct equation for figuring out WATTS is voltage multiplied by amperage equals watts. Fred