Surge protector bypass (1 Viewer)

[FrazzledHunter]

Hopefully this is the right thread.

We have recently bought a new travel trailer and would like to install a hard-wired power surge protector. The brand we've settled on is a 30A Hughes Power Watchdog.
(30 Amp Bluetooth Surge Protector with Auto Shutoff - Hardwired - Hughes Autoformers - https://hughesautoformers.com/product/pwd30-epo-h/)

The Hughes unit does not come with a built-in bypass capability.

Has anyone made or does anyone know the best way to make a bypass capability?

I was thinking a simple bypass circuit as shown below. One half of a Leviton #1288 DPDT center off 30A switch would do it. The switch thrown would be bypass, center off would engage the surge unit. This switch is meant to switch two hot legs and I'm switching a neutral and a hot in this circuit.

Perhaps there's a better way?

 

[e9999]

I don't know anything about that surge protector, but electrically it seems that a bypass like that would work ( although I might think about upscaling the switch a bit for peace of mind if you think that an actual 30A pull is likely when switching on or off).

Why are you thinking about bypassing your expensive protection? Are those too limiting or likely to fail unexpectedly?

 

[FrazzledHunter]

I don't know anything about that surge protector, but electrically it seems that a bypass like that would work ( although I might think about upscaling the switch a bit for peace of mind if you think that an actual 30A pull is likely when switching on or off).

Why are you thinking about bypassing your expensive protection? Are those too limiting or likely to fail unexpectedly?

I would shut power off before doing anything (I sure HOPE I'd remember to do that). The switch advertises it's 30A however I could also use a double pole 30 or 50A breaker instead of the switch I suppose.

So why do this? Well they do fail occasionally and are designed to sacrifice themselves when there's a big enough power surge. You can get replacement "internals" and I could have one in "stock". However I wanted a very quick way to bypass and restore power if I had to. I could get a portable unit that would solve this problem by simply removing/unplugging it but thieves have discovered they also can do this.

Some units like those made by Progressive have a built-in bypass mode. I don't care for the Progressive units for other reasons but they have this great feature.

An alternative schematic is this - it fully utilizes the same DPDT switch by having power going to the center contacts. It more fully isolates the surge unit but I'm not sure it accomplishes anything more:

 

[e9999]

Well, if there was such a surge that the protection trips and fries the sacrificial bit, I would be very hesitant to bypass the protection at that point given the likelihood that the next surge might then take my expensive electronics in the RV. In fact, I would even be hesitant to put in a spare sacrificial bit unless I know that it's very unlikely there would be another surge, or it's a cheap enough spare. If I have batteries and/or a solar system and there is no critical need, I'd just forget the hook up at that point rather than take a chance.

But if I really needed to be able to bypass the protector, I'd consider using quick disconnects like Anderson SBs and just remove the protector and replace with a bit of wiring. That way, there is no chance of accidentally leaving a switch in the bypass position. And cheaper than a high current switch, probably.

 

[FrazzledHunter]

Well, if there was such a surge that the protection trips and fries the sacrificial bit, I would be very hesitant to bypass the protection at that point given the likelihood that the next surge might then take my expensive electronics in the RV. In fact, I would even be hesitant to put in a spare sacrificial bit unless I know that it's very unlikely there would be another surge, or it's a cheap enough spare. If I have batteries and/or a solar system and there is no critical need, I'd just forget the hook up at that point rather than take a chance.

Well yes true. I do travel with a generator and I think I'd hook up to that if I stopped trusting the shore power. Of course, the next campground on our route might be just fine. Ya never know...

 

[e9999]

Good thinking about the protector, though. It'd be quite the situation after an RV park power destroys somebody's electronics or burns the RV down. Would make for a spirited discussion, I would think. But I assume they put in some fine print to preempt any responsibility for that sort of thing. Plus, it'd be hard to prove too.

 

[FrazzledHunter]

Indeed, yet I've had it happen to me and seen it happen to others. Luckily power issues haven't hurt us yet. Mostly it's low power in either poorly wired mom&pop campgrounds or in overcrowded campgrounds with everyone running air-conditioners. The last time it happened to us was at Oregon Inlet campground that took a direct lightning hit in one of those super-cell storms. We were in a tent (it scared the **** out of us) and not connected to shore power. However, the next day the carnage included quite a few RV's with fried electronics and people walking around wondering what to do. It was very quiet, I must say! It was later on that same day I found my cell phone was fried. Dead. My guess it was an electromagnetic pulse that did it but I'm just guessing.

There is another dimension that I forgot to add if I run on generator. These units do more than just protect against surges and sags. They also look for open neutral, voltage on grounds etc... They're smart devices.

Generators do not have neutral & ground bonded and these units will detect a generator as an open neutral and trip. So if you're on generator you HAVE to bypass these surge protectors or get a neutral-ground bonding receptacle to plug into your generator. A switch seems to cover all cases and is the way I'm leaning.

 

[e9999]

Given your history, you might consider installing a lightning rod on the RV too...

 

[FrazzledHunter]

Given your history, you might consider installing a lightning rod on the RV too...

You might be on to something here. The RV frame, internal studs, skin and roof are 100% aluminum. If I run a ground rod from the frame I think I have the perfect lightning rod. Maybe even a pretty good faraday cage. So don't fear lightning, embrace it! What a great idea!

I'll get to work.

 

[e9999]

LOL. You could rig something up with capacitors to capture the energy. Then never mind the puny shore power and its foibles.

 

[FrazzledHunter]

LOL. You could rig something up with capacitors to capture the energy. Then never mind the puny shore power and its foibles.

I'll have to size the capacitors. Lightning is somewhere between 10-100 million volts and 30,000A. So I'll have to give this some thought. I'll also have to run this idea by my wife and she may not like it.

Seriously, I 'm concerned about what that Hughes device will do if it sees bypassed power with power at input & output as in schematic 1 or on output only as in schematic 2. Will it explode?

The green ground also worries me. Is it a pass-through or possibly connected when it has power?

I dunno exactly how these things work.

I'd just FAFO but it costs almost $300 so blowing one up would hurt.

 

[e9999]

If it's a good disconnect, I can't see that either layout would cause the protector to experience any serious problem afterward (outside of some unlikely weird situation with very high voltages or some other odd issue, possibly). Of the 2, the second is perhaps a bit safer (wrt shorts, body contact etc) if it is no longer connected on one side after bypass but that does not seem very significant.
In either case, though, yes, you'd want to make sure you still have ground/green going through after disconnect. That would depend on the construction of the thing and how it is disconnecting things. If not sure, I'd bypass the green/ground wiring as well.

 

[FrazzledHunter]

OK so I've been thinking (UH OH) about what would make a great bypass solution. Maybe this is dumb. But if the solution doesn't seem to exist then why not invent one?

I'm remembering back to my time in industrial control rooms where there were walls of controls that pulled in and out like an old fashioned fuse block. It was great: if you wanted to replace a module you'd pull it out and slide a new one in. Maybe it was a replacement unit or it was a unit that did something else. So, instead of switches and wondering just what to switch, what i f we eliminated the switching problem by being able to pull the Hughes unit and replace it with the bypass unit. Like the industrial control example?

Industrial control room - start of the idea:

I would start with an old-fashioned fuse block that is designed to work with the cylindrical fuses that have a knife edge like this;

I would then get a 3 pole fuse block that would be set into a box. The input and output wiring would be wired to it. I would then create 2 "modules": one a bypass and one to host the Hughes watchdog unit. Each "module" could be pulled out and replaced as desired. Obviously this would not be done "hot". The connections would be implemented with aluminum angle irons and would mimic the place of the fuses. The base holding hte angle irons would be made of some kind of insulating material, TBD.

 

[e9999]

So IOW you want to replace your expensive "electronic fuse" by a simpler "electrical fuse" after an incident? Yes, that would be safer than a straight bypass by wire if you want to stay connected.
Seems a bit duplicative to me, though, but, eh, sounds like fun if you would enjoy building that.
However, I would pay attention to the reaction time of the passive fuse. If not a very fast one, you may still zap your RV bits. I would hope the electronic protection would be faster, but I have no idea if that is true. And I would definitely stick with high-quality well-documented specced serious fuses, not some unknown generic chinese fuse.

 

[FrazzledHunter]

So IOW you want to replace your expensive "electronic fuse" by a simpler "electrical fuse" after an incident? Yes, that would be safer than a straight bypass by wire if you want to stay connected.
Seems a bit duplicative to me, though, but, eh, sounds like fun if you would enjoy building that.
However, I would pay attention to the reaction time of the passive fuse. If not a very fast one, you may still zap your RV bits. I would hope the electronic protection would be faster, but I have no idea if that is true.

Not exactly, if i understand you. The bypass would be aluminum angle irons slid into the fuse black. Kind of like a penny in the old time screw-in fuse. Remember that the output goes to the currently existing fuse panel. Everything is fused.

 

[e9999]

my mistake. I thought you wanted to use real fuses. Should have read more carefully, sorry. But IMO why not use fuses anyway then if they fit the block as is and you're dealing with a potentially damaging situation? Yes, a bit of scrap aluminum is cheaper, but if we're only talking a few bucks for fuses, may be worth it.

TBH, though, I get how that is all fun to design, but it also seems so much more complicated than Anderson Quick Disconnects (or screw terminals or even Wagos if current allows) for your Hughes protector and some bypass wires... The construction of that Protection module would take some time to make it fit the fuse block, well for me at least. Or did I misunderstand yet again this whole thing?

 

[FrazzledHunter]

my mistake. I thought you wanted to use real fuses. Should have read more carefully, sorry. But IMO why not use fuses anyway then if they fit the block as is and you're dealing with a potentially damaging situation? Yes, a bit of scrap aluminum is cheaper, but if we're only talking a few bucks for fuses, may be worth it.

TBH, though, I get how that is all fun to design, but it also seems so much more complicated than Anderson Quick Disconnects (or screw terminals or even Wagos if current allows) for your Hughes protector and some bypass wires... The construction of that Protection module would take some time to make it fit the fuse block, well for me at least. Or did I misunderstand yet again this whole thing?

Problem is I have 3 lines: gnd, neutral and hot. The hot is 30A 120VAC. 3 fuses would work i suppose. But a fuse should only be on a hot.

 

[e9999]

well, of course, you could use one fuse and 2 bars if you want to save a few bucks. But it is true that if you have a fusebox on the RV already, that bypass fuse would also be duplicative. Not that it would hurt anything. But either way you're back to a situation that is not as safe with the bypass as with the Hughes gizmo, I assume. And personally, I would not take the risk of another zapping event if I have a generator anyway.

 

[FrazzledHunter]

well, of course, you could use one fuse and 2 bars if you want to save a few bucks. But it is true that if you have a fusebox on the RV already, that bypass fuse would also be duplicative. Not that it would hurt anything. But either way you're back to a situation that is not as safe with the bypass as with the Hughes gizmo, I assume. And personally, I would not take the risk of another zapping event if I have a generator anyway.

This is one of those "be prepared" corner cases that has tripped up a few people. I got this idea from Progressive's line of power protectors that have a bypass mode/feature as part of their product.

With the Hughes unit I would only run bypassed if the unit was fried and I was 100% confident of shore power (highly unlikely if the shore power caused the unit to be fried) or I was running on generator.