30amp/ 50 amp hook up

Mattman

Well-known member
Does the unit open the circuit if it goes over 30 amps? Then it's not an issue. If it is just a strait adapter and offers no over current protection then your not protected to what the UL listing was intended for on your cable, panel, internal wiring from your panel to your outlet on the ext of your camper. That's the only point I was trying to make. The adapter dosent need a UL to be sold. It probably can't get one if it has no over current protection. A surge protector / adapter with over current can.
Your not suppose to speed when your drive. But people do. I am just stating that allowing more current to flow to your trailer then it was intended for is a bad idea. Even if you are "monitoring it". You can buy the cord ends and make your own if you wanted to. That's why they sell them.
Accidents are never intended and electricity moves fast.
 

danemayer

Well-known member
I doubt that you will find one with a UL label. Have you seen one?

I have one with a CSA logo - the Canadian equivalent of UL. I'm hard put to imagine that Camco would make and sell an electrical adapter without an agency certification label.

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Does the unit open the circuit if it goes over 30 amps? Then it's not an issue. If it is just a strait adapter and offers no over current protection then your not protected to what the UL listing was intended for on your cable, panel, internal wiring from your panel to your outlet on the ext of your camper. That's the only point I was trying to make. The adapter dosent need a UL to be sold. It probably can't get one if it has no over current protection. A surge protector / adapter with over current can.
Your not suppose to speed when your drive. But people do. I am just stating that allowing more current to flow to your trailer then it was intended for is a bad idea. Even if you are "monitoring it". You can buy the cord ends and make your own if you wanted to. That's why they sell them.
Accidents are never intended and electricity moves fast.

Trailers with 30 amp service have a master 30 amp circuit breaker. So yes, of course the trailer master circuit breaker opens if you go over 30 amps. That's why it's safe to plug your cord into a 50 amp receptacle using an adapter.

And even my dumb old power strips have UL labels. Almost every electrical device gets a UL or equivalent label.
 

avvidclif

Well-known member
Does the unit open the circuit if it goes over 30 amps? Then it's not an issue. If it is just a strait adapter and offers no over current protection then your not protected to what the UL listing was intended for on your cable, panel, internal wiring from your panel to your outlet on the ext of your camper. That's the only point I was trying to make. The adapter dosent need a UL to be sold. It probably can't get one if it has no over current protection. A surge protector / adapter with over current can.
Your not suppose to speed when your drive. But people do. I am just stating that allowing more current to flow to your trailer then it was intended for is a bad idea. Even if you are "monitoring it". You can buy the cord ends and make your own if you wanted to. That's why they sell them.
Accidents are never intended and electricity moves fast.

That's kinda like saying I'm going to burn my house down because I plugged my reading lamp with a 16ga (10a) cord into an outlet that is on a 20a breaker. The RV is protected by a 30a main breaker. As long as the rating on the CORD matches the main breaker all is well. If the cord shorts it will open the pedestal breaker, same for the house. If you draw more than 30a the rv main breaker will open.
 

Mattman

Well-known member
What about all the wiring between The main breaker and the pedistal? A system is only as good as it's weakest point. The 30 amp rated outlet on the side of the camper. There for exceeding more than 30amps on the over current device is a violation of the NEC. Exceeding more than 30amps on your 10/3 cord running the pedistal is a NEC violation. If it's 8/3 you have 40. Assuming your not over 86 degrees F. I just checked my code book. Do what ever you want. I'm stating it is a violation to code. Go ask an engineer.
 

Mattman

Well-known member
How exactly do you imagine that you would exceed 30 amps on the shore power cord without tripping the trailer's main breaker?

Easy. Mouse chews into the feed wiring between the connection receptacle on the camper and the panel. Hot conductor starts going to ground on your camper. The 30amp main in your camper will not trip. Its down stream. It's going to draw more current from the pedistal until it trips the 50. Not the 30 at your panel. You can. Shut the 30 off in the panel, but the fault is still there. It needs the over current up stream to clear it. Not down stream.
 

danemayer

Well-known member
If I'm following, the mouse has to chew the wires just right so there's a partial short to ground that pulls more than 30 amps, but less than 50 amps and that has to stay that way long enough to overheat the wires. Hmm.
 

Mattman

Well-known member
How about a screw, or brittle insulation from running more amparage threw a it than it was intended. 30 amp cable isn't designed to run 30 amps for 24 hours a day, 365 days a years. Continuous loads are rated at 80 percent. Go turn everything on in a trailer and run 30 amps threw it for 4+ hours and tell me how hot your breaker got. I bet it go pretty warm.

There is always a chance of something failing. It's a mechanical device. Have you inspected every inch of your feeder cable on Your trailer? Maybe the installer put a small nick in it when he pulled it. Your talking about something made quickly and cheaply. The chances of it being an issue are very low. But there is still that 1-5000 chance something bad happens. 20 amps extra might not seem like much, but in a high resistant fault it could mean The difference between a tripped breaker and electrical fire.
 

Apropdoc

Utah Chapter Leaders-retired
Vampire mice and rogue screws are not going to force more amperage down the wires to the trailer, the breaker at the pedestal will trip first. If not, you are in for a bad day. Current draw is dictated by usage draw, not short circuits. If you don't believe me please review this webpage, the more you know the better you'll feel https://www.rvtechmag.com/electrical/chapter3.php
 

fritzwell

Active Member
I'm trying to understand somethings here guys so be gentle. On a 50 amp service is there 50 amps on each leg or 25 ? If the OP only has a 30 amp service in his trailer then his power cord is only rated for 30 amp ? So, if he uses the conversion plug at a 50 amp service then he's okay if a 220 / 50 amp service only supplies 25 amps per leg ? What if the 220 / 50 amp service supplies 50 amps per leg on a 120 / 30 amp power cord ?
 

Apropdoc

Utah Chapter Leaders-retired
I'm trying to understand somethings here guys so be gentle. On a 50 amp service is there 50 amps on each leg or 25 ? If the OP only has a 30 amp service in his trailer then his power cord is only rated for 30 amp ? So, if he uses the conversion plug at a 50 amp service then he's okay if a 220 / 50 amp service only supplies 25 amps per leg ? What if the 220 / 50 amp service supplies 50 amps per leg on a 120 / 30 amp power cord ?

On a 50 Amp service there are two wires each carrying 120 volts for 50 Amps, so the individual wires in a 50 Amp cord are going to be 8 gauge or bigger. A 30 Amp service is 1 wire carrying 120 volts for 30 amps with a 10 gauge wire or larger. If you use an adapter for going from a 50 to 30 amp service, only 1 of the 50 amp wires will provide 120 volts. Your trailers electrical power management system will prevent you from drawing too much power from the pedestal.
 

Gaffer

Well-known member
I have one with a CSA logo - the Canadian equivalent of UL. I'm hard put to imagine that Camco would make and sell an electrical adapter without an agency certification label.

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Trailers with 30 amp service have a master 30 amp circuit breaker. So yes, of course the trailer master circuit breaker opens if you go over 30 amps. That's why it's safe to plug your cord into a 50 amp receptacle using an adapter.

And even my dumb old power strips have UL labels. Almost every electrical device gets a UL or equivalent label.

The Chinese are in the habit of counterfeiting the UL label. If it carries a legit UL label or label from the other testing labs such as ETL or CSA, than part of that listing includes the installation instructions which will mandate provisions to limit the current to the rated value by fusing or other approved means. This will be clearly indicated in the products White Sheet.
 

Mattman

Well-known member
Vampire mice and rogue screws are not going to force more amperage down the wires to the trailer, the breaker at the pedestal will trip first. If not, you are in for a bad day. Current draw is dictated by usage draw, not short circuits. If you don't believe me please review this webpage, the more you know the better you'll feel https://www.rvtechmag.com/electrical/chapter3.php

Short circuits don't open breakers and draw no current? So if you take the hot wire off a breaker and put it to ground or neutral the breaker never trips?
That article talks about a delta transformer delivering 120/240. Its says nothing about short circuit ratings and fault conditions. It only describes a trouble free electrical.system.
What I have described it called real world scenaro. Spend some time on a service truck. You will be surprised at the things you find.
 

danemayer

Well-known member
I can see where a problem with shore power cord or internal wiring up to the breaker panel could have a failure that could take longer to trip a 50 amp pedestal breaker than a 30 amp pedestal breaker, and given exactly the right conditions, it could be serious. But as I think about all the problems routinely encountered with campground electric, this one seems relatively low odds.

So my thought is if you want zero risk on your side of the pedestal, skip the adapter and plug your 30 amp shore power cord into a 30 amp receptacle. If you are willing to accept a small risk, go ahead and use an adapter.

If you're worried about who pays if something bad happens, buy a name brand adapter.
 

Bones

Well-known member
I'm in big trouble then. :) I'm constantly plugging my 3 amp devices into 20 amp outlets. :angel::angel::angel:
 

Mattman

Well-known member
Watch this. A simple heater in a 20 amp circuit. Loose connection.
https://youtu.be/_2HyTRxzwXs

What I am describing to you guys is when things go wrong. You can plug a lamp in 800 amp breaker and it will be fine for years until a problem arises. That's where the code does its best to limit problems to avoid injury to people.
We tow our campers all around. Lots of movement. Strange things can happen. That's all my point is. Try to limit the fail points and areas for a problem.
 

danemayer

Well-known member
Watch this. A simple heater in a 20 amp circuit. Loose connection.
https://youtu.be/_2HyTRxzwXs

What I am describing to you guys is when things go wrong. You can plug a lamp in 800 amp breaker and it will be fine for years until a problem arises. That's where the code does its best to limit problems to avoid injury to people.
We tow our campers all around. Lots of movement. Strange things can happen. That's all my point is. Try to limit the fail points and areas for a problem.

This video appears to be showing a completely different situation where neither a 30 or 50 amp pedestal breaker would have made any difference. I'm guessing you're just trying to illustrate that electrical problems can be dangerous. I'd also guess that this video illustrates the reason connections are put inside junction boxes.
 

Mattman

Well-known member
Okay. I give up. It's perfectly safe and with in code to plug a 30 amp rated system into a 50amp over current device. Happy camping.
 

TedS

Well-known member
Okay. I give up. It's perfectly safe and with in code to plug a 30 amp rated system into a 50amp over current device. Happy camping.

I see no difference than feeding 20-amp breakers from a main 100-amp breaker in a house. Or feeding a secondary breaker panel from a main 100-amp service.
 

212Pilot

Active Member
All this electrical stuff is very interesting and a little scary. Is it safe to plug a 50A cord into any 220v receptacle? Is there something I should check to make sure it will work for my trailer? A potential spot I am looking at to stay for a few weeks has a 220V receptacle but it is on a double 100A circuit breaker. Is it safe to use?
 
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