30 amp vs 50 amp wiring

[Rvlegaleagle]

I have two questions about 30 vs 50 amp wiring. The first question is the "gauge" of the wiring used inside "to build the rig" any different between the two types of service or is it just in the panel itself? Hope I am making sense here. In other words, is the internal wiring used when building the rig the same gauge for a 30 amp and 50 amp service? The second is, if you get a 30amp service with the rig, what is involved in making it a 50amp service? Thanks in advance.

[twinboat]

From the power cord to the breaker box, 50 amp uses heavier wire then 30 amp. 6 gauge for 50 amp and 10 gauge for 30 amp.

That includes the transfer switch.

From the breaker panel out, all is the same as any house.

50 amp service is 50 amp, 240 volt service, split into 2, 120 volt services at the breaker panel. The panel will have 2, 50 amp breakers.

30 amp service is 30 amp 120 volt service. The panel will have 1, 30 amp breaker.

[select55]

Originally Posted by Rvlegaleagle

I have two questions about 30 vs 50 amp wiring. The first question is the "gauge" of the wiring used inside "to build the rig" any different between the two types of service or is it just in the panel itself? Hope I am making sense here. In other words, is the internal wiring used when building the rig the same gauge for a 30 amp and 50 amp service? The second is, if you get a 30amp service with the rig, what is involved in making it a 50amp service? Thanks in advance.

for a general answer yes it is. to make it 50amp you need a 50amp shore power cord, a 50amp transfer switch (if its has a gen set system)
a extra hot from transfer switch to panel;; 50amp double breaker and 50amp RV panel (basic rundown)

[wa8yxm]

Regarding wire size.. Would you try to draw 50 amps through a 30 amp fuse?

Well you draw more than 30 amps through a 30 amp rated cord for any period of time and it's likely to melt the wires.. Just like that fuse, Only where as the fuse is DESIGNED so if the wire melts no secondary damage is done.. The cord may have a tendency to introduce you to a group of folks who still make house calls....... THE FIRE DEPARTMENT.

[jacwjames]

It's not only the size of conductor but the number of conductors.

Your 30 amp system has 3 wires (black-line, white-neutral, green-ground). It should be 10 gauge wire to the main panel. From there the rest of the wiring should be the same.

A 50 amp system has 4 wire, with the additional being another black wire. Each of the black wires are 120 volt but alternating cycle making a total of 240 volts. The gauge of the wiring is #6 which is good for 50 amps each leg, so in reality you have 100 amps of available power.

Depending on the main panel it might be possible to replace the main wiring. If they did use a 240 volt panel it would be feasible to do this. If they didn't use a 240 volt panel the whole thing would have to be changed, still probably doable but not as easy.

All the individual circuits should be able to be used.

[Rvlegaleagle]

Who is better than you guys!! And fast too

So if I got this right, what I am calling the "internal" rig wiring (appliances, outlets, lights etc) for a 30amp service uses the same "gauge" wiring as a 50 amp service at least to the panel. It is from the panel out to the transfer switch and power cord where there is a difference between the two services as far as the "gauge" of the wires are concerned plus an additional wire for the 50amp. Ok.

Would it be fair to say then you really only need a 50amp if you have two A/Cs you want to run them both at the same time? Will the 30amp service or the gen run everything all at once on a 30amp service? Thanks again.

[Kiawah]

No you can't run everything on 30A service. As a rule of thumb, I run only two major things, say 1 of the 2 A/C's and the microwave, or 1 A/C and elec h2o heater. You need to remember that the converter(charger) also uses some power, as well as entertainment and lights and refrig.

50 amp service has effectively 3 times the amount of power available than 30 amp service. As mentioned before 50 amps service is two legs of 50 amps, for a total available current of 100 amps. Thirty amp service is just 30 amps.

[twinboat]

My 30 amp MH has 1 AC, gas/electric fridge, microwave and converter.
The water heater, heat and stove are gas only.

It was layed out that way, to work well on 30 amp service.

[select55]

Originally Posted by Rvlegaleagle

Who is better than you guys!! And fast too

So if I got this right, what I am calling the "internal" rig wiring (appliances, outlets, lights etc) for a 30amp service uses the same "gauge" wiring as a 50 amp service at least to the panel. It is from the panel out to the transfer switch and power cord where there is a difference between the two services as far as the "gauge" of the wires are concerned plus an additional wire for the 50amp. Ok.

Would it be fair to say then you really only need a 50amp if you have two A/Cs you want to run them both at the same time? Will the 30amp service or the gen run everything all at once on a 30amp service? Thanks again.

actually you can run 2 ac units at same time but you cant start both at the same time especially if their hot .You could on 30 amps run one and then start the other. thing is then you cant run other stuff at the same time
you can run two AC units on gen set as along as the gen set is large enough. SO if your happy running one AC and say HWH and maybe
some small draw stuff then 30 amps is plenty

[Rvlegaleagle]

I think my statement or question was not clear. If you have a 30amp service, the usual 1 a/c, micro, water heater, rv ref, ac outlets using a laptop, phone charger, coffee pot and tv ......lets say in a typical class C, and you are either plugged in or are on the usual 4k gen, can you run everything at once and be OK?

I will get to adding the solar part later on after I understand this part first Thanks again!

[vsheetz]

Originally Posted by Rvlegaleagle

I think my statement or question was not clear. If you have a 30amp service, the usual 1 a/c, micro, water heater, rv ref, ac outlets using a laptop, phone charger, coffee pot and tv ......lets say in a typical class C, and you are either plugged in or are on the usual 4k gen, can you run everything at once and be OK?

I will get to adding the solar part later on after I understand this part first Thanks again!

One air conditioner plus other stuff - yes, you are typically ok. Unless you want to run multiple other high current draw stuff all simultaneous then you may have a problem (such as Water heater, coffee pot, microwave, and converter/battery charger). This would be uncommon scenario.

[Kiawah]

I think my statement or question was not clear. If you have a 30amp service, the usual 1 a/c, micro, water heater, rv ref, ac outlets using a laptop, phone charger, coffee pot and tv ......lets say in a typical class C, and you are either plugged in or are on the usual 4k gen, can you run everything at once and be OK?

It's going to vary, based upon your individual devices in your coach. I've done a current inventory on mine, monitoring the current of each individual device. This should give you an idea of current consumption:


- 14 amps Microwave, 12amps Convection oven
- Refrig is 1a when compressor running, 8a if it kicks into defrost mode
- Each A/C is 12->15 amps
- Washer 1a when washing, 4a when spinning
- Dryer 12a on high heat, 7a on low heat
- H2O heater 11a
- Diesel engine preheat 5a
- Fireplace 15a
- TV's/Entertainment, 0->10a depending upon how many TV's/Sat/etc on
- Converter (5->15 amps), based upon configuration settings, battery charge, and 12v usage (lights, fans, radio, water pump, etc)
- GFIC and regular outlets, depends upon what all is plugged in. Toaster, coffee maker, hair dryer, space heaters all high amps (can be 10-15a each). Laptops are only couple hundred watts.
- Motors can have higher current surges when starting (eg AC's, refrig motor, washer/dryer motors, mwave fans).

You should also note, that depending upon how good the CG and coach wiring is, a current numbers can be more. If the voltage is lower due to the transformer or resistance of cabling (a 30amp cable, will have a higher resistance/foot than a 50amp cable).........then the current draw will increase (due to wanting to draw the same power consumption of an AC, for instance).

In my case, I have 50amp shorepower service which is a total capability of 100 amps (if loads were ideally balanced perfectly on both legs, which is impossible). My generator puts out 67 amps max.

We camp on 30a shorepower quite a bit, and have camped weeks on 20amp service (obviously weather dependent locations). It's a matter of managing devices carefully, wife knows she has to let me know before using hairdryer for instance, so I can turn other things off.

[MisterT]

think about the differences this way:

'50a service' is actually up to 100amps, which is more than TRIPLE 30a service...
(you have TWO 50a incoming power lines, versus a single 30a line - your breaker box splits these into two 'sides' of your power system, which is why you have two 50a Main Breakers, but all appliances and 110v outlets use the same wiring as with any system)

While it's easy to assume that you could run most EVERYTHING simultaneously on 50a service, you certainly could NOT on 30a service - everything being the same(though most will tell you that even a house with 200a service does NOT mean it's designed to run everything AT THE SAME TIME)...

once you get used to 'reducing' your usage on 30a service, such as turning off the a/c unit when using the microwave, you will have begun to realize that Electricity Management is an entegral part of the daily RV lifestyle, especially the more you travel and come across various different power source options.

[Rvlegaleagle]

"once you get used to 'reducing' your usage on 30a service, such as turning off the a/c unit when using the microwave, you will have begun to realize that Electricity Management is an entegral part of the daily RV lifestyle, especially the more you travel and come across various different power source options."

Exactly! You know what they say about "planning" while he is "laughing". I am just trying to learn as much as I can BEFORE getting out there. The hardest part so far seems to be what rig to get and the 30amp vs the 50amp seems to be a jumping off part for me. Looking at a 30+ class C or class A (gas). Have two golden retrievers, Plaintiff and Lucky, and so anything under 30 will be more difficult for all of us.

The plan..there we go again...is to go to mostly National Forest, State parks and BLM, etc....not a particular fan of RV parks although there are times I am sure. Nature and boon-docking (2 to 4 months at a time inching up to mostly full time ) are much more appealing. You guys have been GREAT and any additional comments or experiences are always welcome! Thanks