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50/30 amp surge protectors

jstaffon
Explorer
Explorer
I have two questions that are somewhat related.

1. I seem to recall that the 30 amp circuit wiring is basically 1/2 of the 50 amp circuit. However, I had weird things happen in my camper when 1/2 of the 50 amp service at the pole failed. Results I hadn't anticipated. It very well could have been the internal wiring of the camper. I never really understood the issue. Thus my question...If I buy a 50 amp surge protector and use a 50 to 30 amp pigtail, will the surge protector work properly?

2. A friend has a Class A with a built in 50 amp surge protector. If he uses a 50/30 amp pigtail and hooks to a 30 amp pole, will his built in protector work properly?

Thanks in advance!

Jeff.
2020 GMC Sierra 3500HD Denali, Duramax
2016 Forest River Rockwood 8299BS

Jeff
Idaho Falls, Idaho
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16 REPLIES 16

pianotuna
Nomad III
Nomad III
Since you are so "outside the box" I would have expected your brilliance to intuit what I was doing. Testing voltage under load before plugging in the RV is quite clear. It doesn't need to be explained. And I've been advocating it for many years.

I may be the only one that does check voltage under load (but I doubt that). There are other things I may do that few others do as well. Such as limiting the draw to 80% of the shore power supply. Or treating plugs with deoxit. Or using an autoformer when voltage drops below 107.

SoundGuy wrote:
Fact is, you didn't say you used a dummy load to emulate the load your rig would put on the supply service once plugged in, in fact I'd bet you're the only one that does. You want to be clear? - then post what you actually mean, otherwise your post is useless. :S
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

SoundGuy
Explorer
Explorer
SoundGuy wrote:
Impossible ... when you "check the pedestal" before plugging in it's not under load, rather it's unloaded. :R


pianotuna wrote:
SoundGuy,

You need to think "outside the box" a little more. Checking voltage under load, before plugging in the RV, is easy.


Me? Need to think "outside the box"? Ha, now that's funny. :W

Fact is, you didn't say you used a dummy load to emulate the load your rig would put on the supply service once plugged in, in fact I'd bet you're the only one that does. You want to be clear? - then post what you actually mean, otherwise your post is useless. :S
2012 Silverado 1500 Crew Cab
2014 Coachmen Freedom Express 192RBS
2003 Fleetwood Yuma * 2008 K-Z Spree 240BH-LX
2007 TrailCruiser C21RBH * 2000 Fleetwood Santa Fe
1998 Jayco 10UD * 1969 Coleman CT380

jstaffon
Explorer
Explorer
Thanks all for your explanations and advice! As usual, you've given me a few things to consider. Cheers to all!
2020 GMC Sierra 3500HD Denali, Duramax
2016 Forest River Rockwood 8299BS

Jeff
Idaho Falls, Idaho
---

pianotuna
Nomad III
Nomad III
SoundGuy,

You need to think "outside the box" a little more. Checking voltage under load, before plugging in the RV, is easy.

I created an adapter that has a 30 amp male plug which feeds a multiple outlet box. Into the box, I plug a polarity checker, a kill-a-watt meter, and a hair drier--which provides the load. First test is polarity, then I check voltage, then I turn on the hair drier and observe the voltage.

If the pedestal passes, only then do I plug in the RV, which has an OEM 30 amp service.

If the voltage drop is excessive (i.e. below 107) then I plug in the autoformer at the RV end of the cord(s).

I deliberately limit my "draw" to 80% of the rated value. So on a 30 amp pedestal I "set" for 24 amps, and on a 15, 12 amps. On 15, I turn on the load support feature of the inverter/charger.

On a 50 amp service, I use a "break out box" which has a 30 amp breaker on one leg, and twin 20 amp breakers on the other leg. It is not balanced of course. On 50, I do limit the OEM 30 to 30 amps. The twin 20 amp legs feed the dual auxiliary shore power cords. They are used to power extra electric heaters for winter time use. In the summer time I can move the water heater to one of the auxiliary shore power cords.

SoundGuy wrote:
Impossible ... when you "check the pedestal" before plugging in it's not under load, rather it's unloaded. :R
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

SoundGuy
Explorer
Explorer
pianotuna wrote:
I do check the pedestal each and every time under load, before I plug in.


Impossible ... when you "check the pedestal" before plugging in it's not under load, rather it's unloaded. :R
2012 Silverado 1500 Crew Cab
2014 Coachmen Freedom Express 192RBS
2003 Fleetwood Yuma * 2008 K-Z Spree 240BH-LX
2007 TrailCruiser C21RBH * 2000 Fleetwood Santa Fe
1998 Jayco 10UD * 1969 Coleman CT380

pianotuna
Nomad III
Nomad III
Solution surge only = little protection

Solution surge with energy management system = much better protection. Low voltage cut out is too low for my tastes. It leaves you to your own devices for power making generator ownership pretty much necessary

Solution autoformer to boost low voltage (which causes MOST of the problems) = good protection, particularly if some surge protection is added. Low voltage is boosted up to a safe level.

Solution autoformer conjoined to a ems. The best of both worlds.

Since I have a beer budget, and can't afford to replace expensive items I chose the Sola Basic autoformer to which I have added surge protection. I do check the pedestal each and every time under load, before I plug in.
Regards, Don
My ride is a 28 foot Class C, 256 watts solar, 556 amp-hours of Telcom jars, 3000 watt Magnum hybrid inverter, Sola Basic Autoformer, Microair Easy Start.

wa8yxm
Explorer III
Explorer III
jstaffon wrote:
I have two questions that are somewhat related.

1. I seem to recall that the 30 amp circuit wiring is basically 1/2 of the 50 amp circuit. However, I had weird things happen in my camper when 1/2 of the 50 amp service at the pole failed. Results I hadn't anticipated. It very well could have been the internal wiring of the camper. I never really understood the issue. Thus my question...If I buy a 50 amp surge protector and use a 50 to 30 amp pigtail, will the surge protector work properly?

2. A friend has a Class A with a built in 50 amp surge protector. If he uses a 50/30 amp pigtail and hooks to a 30 amp pole, will his built in protector work properly?

Thanks in advance!

Jeff.


50 amp circuits are 120/240 volt Two hot legs divided by a neutral
30 app is 120 only one hot leg and the neutral so in this respect your "Half" is correct but as the TV sales types say "Wait there is more"

When half the circuit at the pole failed. half the RV shut down. as it should.

WHen you plug a 50 amp rig into a 30 amp outlet using an adapter. Assuming the Adapter is good The one LEG is fed to BOTH sides of the 50 amp service so everything works.. Just now at one time.

IF you have a 50 amp RV then you get a 50 amp SURGE guard. it works just fine on 30 amps. No problems. Save in some parks where ... Well the problem is the park.
Home was where I park it. but alas the.
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2naEagle
Explorer
Explorer
You really need a EMS it does a lot more than just surge protection.
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time2roll
Nomad
Nomad
Bob Sue wrote:
When using a 30amp service, what gets plugged in first? The reducer cord, or the surge protector?
I would connect the chain and lastly plug into the pedestal.

jstaffon
Explorer
Explorer
Bob Sue wrote:
When using a 30amp service, what gets plugged in first? The reducer cord, or the surge protector?


It would be the 30 amp pigtail followed by the surge protector followed by the 50 amp RV cable.
2020 GMC Sierra 3500HD Denali, Duramax
2016 Forest River Rockwood 8299BS

Jeff
Idaho Falls, Idaho
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Bob_Sue
Explorer II
Explorer II
When using a 30amp service, what gets plugged in first? The reducer cord, or the surge protector?
Bob&Sue
2021 Cedar Creek 34IK
2011 Ford F-250
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Pullrite Superglide

John_Wayne
Explorer II
Explorer II
Just remember you will not be able to power as many things at the same time with the 30 amp plug. 50 amp run both A/C units 30 amp only one at a time.
John & Carol Life members
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time2roll
Nomad
Nomad
Yes and Yes. Get a protector that matches the RV service.

Old-Biscuit
Explorer III
Explorer III
ScottG wrote:
When your plugged into 50A and one leg fails, you are losing half of the circuits in your RV - all the stuff on that leg.
When you plug that same RV into 30A with an adapter, the adapter gangs those two legs in your RV together. So you have power on both legs.

ALso, 30A is not half of a 50A circuit because there's 50A available on both legs for a total of 100A.


Exactly^^^^^

30A....3600W Total available
50A....6000W per Hot Leg/12,000W Total available


To answer your questions
1) YES
2) YES
Is it time for your medication or mine?


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