Power protection with generator
Printed From: R-pod Owners Forum
Category: R-pod Discussion Forums
Forum Name: I need HELP!!!
Forum Discription: Perplexed/need help with a problem - ask here
URL: http://www.rpod-owners.com/forum_posts.asp?TID=13163
Printed Date: 13 May 2025 at 3:30pm
Software Version: Web Wiz Forums 9.64 - http://www.webwizforums.com
Topic: Power protection with generator
Posted By: Shane
Subject: Power protection with generator
Date Posted: 06 Sep 2019 at 5:17pm
|
Do you still need to use a power protection device if you are using a generator for you 30amp power? I think common sense would be yes but just curious if its necessary. ------------- ENGINE 55,TRUCK 44,BATALLION 12 |
Replies:
Posted By: mjlrpod
Date Posted: 06 Sep 2019 at 5:48pm
|
That would depend on if the generator can produce more than 30 amps. But the best answer is, you can never be too safe. ------------- 2017.5 Rp-172 2020 R-pod 195 2015 Frontier sv 4.0L 6cyl I'll be rpodding |
Posted By: StephenH
Date Posted: 06 Sep 2019 at 7:38pm
|
If you want to use power protection, the smart ones might not let power flow since the generators have a floating ground. In that case, you would need to purchase or make (really simple) a bonding plug to tie together the neutral and ground terminals. Then the circuit analyzer will be happy and let the current flow. Bonding plug: Take one 15A male plug sold at the hardware store for repairing extension cords. One meant for outdoor use is probably best for this. Open the plug and locate the neutral and ground terminals (usually, hot is brass color, neutral is silver color, and ground is green). Take a short piece of 10 or 12 gauge wire and connect the neutral (silver) terminal and the ground (green) terminal. Do NOT connect anything to the hot (brass color) terminal! Close the plug and (if desired) squirt some silicone sealant in the hole through which a cord would normally run to make it water resistant. Use of bonding plug: Plug the bonding plug into one of the 15A outlets on your generator. Plug your circuit analyzer or extension cord into one of the other outlets (15A or 30A as appropriate). Start your generator and run as normal. ------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: podwerkz
Date Posted: 07 Sep 2019 at 12:42am
|
Need to? No....but of course you can add protection for your own peace of mind. But most protection devices are designed to prevent electrical spikes and surges that can happen to the grid/shorepower system. Those spikes and surges normally occur upstream somewhere due to an electrical storm, lightning, etc, or possibly, physical damage to the lines or poles somewhere on that part of the grid. Most decent quality generators have little chance of producing a damaging spike or surge....but of course, anything can happen. ------------- r･pod 171 gone but not forgotten! |
Posted By: TheBum
Date Posted: 09 Sep 2019 at 10:11am
Or, most generators have a ground terminal on them. Just drive a metal rod into the ground and have a wire with a clamp on one end and a spade or loop terminal on the other end. Then just connect the terminal to the generator and the clamp to the rod. However, There is very little chance of a power spike with an inverter generator. We don't use our power protection when running on generator. ------------- Alan 2022 R-Pod 196 "RaptoRPod" 2022 Ram 1500 Lone Star 4x4 Three cats |
Posted By: StephenH
Date Posted: 09 Sep 2019 at 12:05pm
|
An effective ground rod must be driven in quite deep. If one is in a rocky area, that might not be so easy. A shallow ground rod won't provide much protection. When I was stationed at Fort Hood, we would drive in copper ground rods that were about 8' long. To get them back out, we hooked a chain from one of the trucks to pull it out. This might not be acceptable in some places. One does not want to just drive a ground rod in without knowing whether there is something buried there that might be damaged (water, power, sewer, etc.
------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: GlueGuy
Date Posted: 09 Sep 2019 at 2:18pm
|
+1 A ground rod needs (usually) to be about 6-8 feet into the ground. Once you do that, you may not be able to get it out again. That, and you have no idea what may be underground. ------------- bp 2017 R-Pod 179 Hood River 2015 Ford F150 SuperCrew 4WD 3.5L Ecoboost |
Posted By: StephenH
Date Posted: 09 Sep 2019 at 8:41pm
|
An alternative is to dig a trench and bury the 8' ground rod horizontally. I think most campgrounds would frown on this type of digging. That is why a bonding plug is a good alternative that works.
------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: offgrid
Date Posted: 10 Sep 2019 at 2:46am
|
We need to differentiate the terms "bonding" and "grounding". Bonding connects the metal parts of an electrical system together as well as to the neutral (white) conductor. Grounding provides a connection between earth ground and this bonded system. RV's have no grounding system themselves, when grid connected the ground connection is provided by the connection to the RV park or home electrical system. So when you are disconnected from that and are running on a generator there is no earth ground connection. That's OK as long as everything is bonded to the trailer chassis. The trailer electrical system (both the neutral and any metallic components) are bonded to each other and to the chassis at the power panel. So if you connect your three wire (two plus ground) power cord between the generator and the receptacle on the trailer (no power protection device) everything except the chassis of the generator itself has been bonded. If the generator is mounted on the RV then by code its chassis is supposed to be bonded to the RV chassis, which can be done using the generator ground connection point. That point is not connected to neutral at the generator receptacles, just to the generator chassis and outlet grounds. At least that's how my Honda is wired. Check your generator manual to be certain. If the generator is not mounted on the RV and you have a circuit analyser that is looking for a connection between the ground and neutral conductors feeding the trailer receptacle, as StephenH says it will refuse to connect unless those two conductors are already bonded before entering the trailer. StephenH's bonding plug solution will work for that. A ground rod connected to the generator ground point would not, because the neutral would still not be bonded at the generator. The only caveat I have is that the bonding plug needs to be able to carry the full current output of the generator. So if that is say 30A i wouldn't use a 15A plug and 12 gauge wire for that purpose. For myself, I don't use a circuit analyser when running on my Honda. Its not like there are miles of power lines waiting to be struck by lightning feeding into the trailer. The likelihood of getting a lightning induced spike on the 25 foot cable to the generator is negligible, and if it did happen the strike would be so close that I would be more worried about changing my shorts than fixing my trailer wiring.  ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |
Posted By: StephenH
Date Posted: 10 Sep 2019 at 8:13am
|
Thanks for the thorough explanation and the humor at the end. I was sitting in the apartment I was renting in Yongsan, Korea working at my computer. I heard a loud SNAP and my computer shut down. It was during a thunderstorm, and I think the lightning struck a telephone pole near me. The computer was mostly okay, but my surge protector was fried as was the modem. I use the bonding plug and since my generator only has the two 15A outlets, and since the distance to be bridged is so short (more like 2" or less of wire which includes the wrapping of the ends around the terminals, 12 gauge is probably okay, 10 gauge better. Agreed though that if I had a 3500 Watt generator, I would want to use a heavier wire for bonding. However, that would present the problem of how to do so because most generators I have seen may have two 15A outlets but only one 30A outlet available. ------------- StephenH Happy is the man that findeth wisdom,... http://www.rpod-owners.com/forum_posts.asp?TID=7712 - ouR escaPOD mods Former RPod 179 Current Cherokee Grey Wolf 24 JS |
Posted By: offgrid
Date Posted: 13 Sep 2019 at 4:31am
|
Back before solar got cheap our main customers were operators of remote telecom sites, many of which are on tops of mountains. So I had to learn about lightning protection and spent someh pretty interesting nights in electrical storms.
The thing about lightning is that essentially only big power circuits will survive a direct strike. Those involve hundreds of kiloamps. You have to have lightning electrodes, heavy conductors, and robust grounding systems to handle that. Under the cone of protection provided by the lightning electrode system you still have to worry about damage from electrical surges induced in the circuit wiring. These currents are induced by the rapidly changing electromagnetic fields created by the lightning itself, similarly to how an antenna or a generator works. The induced currents are proportional to how much magnetic flux passes through the circuit loop. That’s why sensitive electrical signals are sent via wire pairs that are twisted together to avoid creating a loop. For the same reason we quickly learned not to daisy chain our solar modules together in big loops. The induced currents in large loops or grid connections can still be in the range of kiloamps or 10s of kiloamps but they are short enough in duration (microseconds) that they can be handled by various types of transient suppressors, the primary ones being metal oxide varistors. Those are rated in kilojoules of energy dissipation capacity which is why you see those specs when shopping for RV surge protectors. Typical ones might be rated at around 4 kilojoules which is about 1 watt hour. Doesn’t sound like much but it’s being dissipated in a few microseconds so the power levels are huge. Anyway the point is that with a portable generator that is ungrounded and a 25 ft RV cable that doesn’t create a large wire loop, there really isn’t the need for a surge protection device like there is when you’re connecting to an RV park’s big grounded grid connection. It won’t hurt to have it but just a simple surge protector would be better than a fancy smart circuit analyser in this case because that wouldn’t require an additional bonding plug to trick it into turning the juice on. ------------- 1994 Chinook Concourse 1995 RV6A Experimental Aircraft 2015 Rpod 179 - sold |