Electricity 101 - Reading Recommendations?

[PharmGeek]

For people that have a near total ignorance about or very superficial understanding of electricity and such, do any of you have any good references, articles, websites, or general advice to help familiarize newb's to important considerations about electricity when using a TT?

I have a general understanding of it all, but I do not want to fry any of my appliances once I get my TT.

I understand there is 30amp 110v service to run appliances (although if think it will not run my 15k btu ac unit?), and this system if 2-3 appliances are used at same time, could blow a fuse. Then 50 amp service 120v and I THINK there is 50amp 240v??

I know that there are different plugs for these different things, so they are from that standpoint "idiot proof"..but I read that there are some older 220 outlets in some places that look very similar to others and if plug into that.....not good.

Also, I read that it is a good idea to check and keep an eye on voltage of your electrical source to ensure voltage does not drop below say 100v and damage your appliances?

Anyway, Clearly I am not an electrical expert, but this brings up the point that if I had some good references, videos, etc to review, I could beef up my understanding in this subject as well.

Also as it relates, I was talking to my contractor about my plans for my electrical home hookup and had read on this forum to avoid the pitfall of a contractor installing 220 in error...(assuming I read that correctly)...and he insisted that to run AC units such, I would need 220...

Ok, any reading recommendations or nuggets of wisdom would be appreciated!

Thanks.

[A W Warn]

Your contractor needs to be educated, prior to installing your outlet. You need a 120v 30 amp RV outlet. This one is available at Lowes or Home Depot.

An Airstream does not have a 240v system (that I am aware of), unless someone has modified it.

I have no suggestions for reading material, except an owner's manual has the wiring diagram.

[AirsDream]

Strongly suggest you Google to find, and read, two articles that are entitled something like "The 12 volt side of life." Much straightforward information for RVers.

As to your contractor, get another one. He obviously doesn't know what he's talking about. Even for homes, there are many older (and current production?) window air conditioners that run on 120v. Yes, for a whole-house unit that sit outside on a concrete pad, 240v. is needed. But you're only talking about powering your trailer, with it's much smaller air conditioner, etc. And no Airstream I've ever seen takes 240v. ('course, I've not seen them all! - so read your trailer's manual) If you can get someone to run a 120 volt, 30 amp. circuit with the proper receptacle - the one that will accept the plug on the end of your trailer's shore power cord, and IF the receptacle is placed in a location where you don't need to use extension cords, you should do fine.

It is true that such circuits and outlets are not typical for home installations, so your electrical contractor may have to do some research on code for wire size ... though I'm guessing, I'd expect that for any run long enough to be near a trailer parking space, he'd need to up the wire gauge to avoid serious voltage drop.

Then before / while using, be sure to get some sort of line voltage measuring device. A good meter will do fine, or just get one of those small units available at RV supply places such as Camping World for maybe $20 and keep it plugged in where you can see it. It will tell you most of what you need to know (at home and on the road and on generator power if you choose that route) about what voltage is actually reaching your coach's wiring.

[Skater]

The plug that's similar is for dryers, and it is a 240 volt plug. Normally they wouldn't be installed outside because most people have their dryers inside the house.

The stories you've read on here are usually because an electrician installed a new outlet and wired it to 240 volts, not because they plugged into one that was there all along and ignored.

Sounds like yours is confused about the 120 volt 30 amp plug thing. If necessary, remind him that window air conditioners also use 120 volt at 15 amps (or less).

[DKB_SATX]

Here's a good site for research.

30A shore power is fine for a 15k BTU AC unit, and anything else except a high-load appliance like a microwave or toaster-oven concurrently w/ the AC. With a high-efficiency AC unit or after the compressor has started and settled down to "run" load, you might get away with more but if the compressor is trying to cycle on when someone's using a blow-dryer on high or microwaving something, it may overload.

The 30A RV socket is clearly marked for 120v service, old 3-prong dryer outlets are a different pin layout and the cord won't fit. Tell your contractor he's not an electrician if he can't read that simple spec on the socket. If he tells you he is, tell him he's not a very good one. Then check the 30A RV socket with a voltage meter before plugging in an Airstream in case he's one of those "I know too much to follow the specification for this socket" types.

A 50A RV socket is a different animal... it's 240v service but each appliance in the trailer is STILL 120V. There are just 2 groups of circuits, each at 120V, running off one "leg" of the 240V service. That's why everything still works if you use a 30A-50A adapter, you just won't have enough juice to run both ACs at once.

[DKB_SATX]

Originally Posted by Skater

The plug that's similar is for dryers, and it is a 240 volt plug. Normally they wouldn't be installed outside because most people have their dryers inside the house.

The stories you've read on here are usually because an electrician installed a new outlet and wired it to 240 volts, not because they plugged into one that was there all along and ignored.

Sounds like yours is confused about the 120 volt 30 amp plug thing. If necessary, remind him that window air conditioners also use 120 volt at 15 amps (or less).

Some window units actually use 240v service, so that won't convince the contractor.

[lewster]

PG,

Tell your electrician to get educated on the needs of your RV. There are numerous threads on these Forums about electricians who automatically thought that the 30 amp/120VAC that they were requested to install should have been a 30 amp/240VAC outlet and when the owner connected to it (yes, the plug pattern will fit) they blew out numerous 120VAC electrical appliances in their trailers, which the contractor then had to replace.

YOU ARE NOT INSTALLING A RESIDENTIAL CLOTHES DRYER!!!!!!!!

THIS FOR A RECREATIONAL VEHICLE!!!!!!!!!!!!!!!

If they can't come to grips with installing a 30 amp/120VAC circuit for your trailer that has a single hot wire, a neutral and ground, THEN FIND SOMEONE ELSE who does!

[PharmGeek]

I have a brother that is a journeyman electrician....when I discussed it with him he said he knew right off the bat what I meant and agreed.

My contractor seemed hung up on this issue...I told him very very clearly that I am certain that he was wrong on this point....hes a good guy, very skilled, but obviously lacking in this particular matter...

Bottom line is, that before I plug my crap in, I should check the voltage of whatever I hook into...

I kinda do not understand the 50 amp service 240 thing...

Also, for the purposes of my home use of the trailor...what setup would I need to run both AC units?

Ill read through the suggested links starting tonight! Thanks for the info you all

[Protagonist]

Originally Posted by PharmGeek

For people that have a near total ignorance about or very superficial understanding of electricity and such, do any of you have any good references, articles, websites, or general advice to help familiarize newb's to important considerations about electricity when using a TT?

Ok, any reading recommendations or nuggets of wisdom would be appreciated!

The arts of boat maintenance and RV maintenance are very similar, when you get up to live-aboard boat size. There are a number of excellent books on marine electical systems that cover both 12v and 120v, that can be mined for information that will work on RVs as well. Nigel Calder's Boatowner's Mechanical and Electrical Manual is excellent. Available at B&N and other booksellers.

[dlb435]

I work in the electrical power industry. I really can't suggest any books suitable for a little light reading. Most good electrical courses run about two years. Then there is the small matter that not all electricians are the same. We often refere to common electricians as "house wire" electricians. The limit of their knowledge was learning enough of the NEC to pass the test. (or getting a friend to get them all the answers)
My best suggestion is to find a good electrician that comes highly recommended.

[DKB_SATX]

Originally Posted by PharmGeek

I have a brother that is a journeyman electrician....when I discussed it with him he said he knew right off the bat what I meant and agreed.

My contractor seemed hung up on this issue...I told him very very clearly that I am certain that he was wrong on this point....hes a good guy, very skilled, but obviously lacking in this particular matter...

Bottom line is, that before I plug my crap in, I should check the voltage of whatever I hook into...

I kinda do not understand the 50 amp service 240 thing...

Also, for the purposes of my home use of the trailor...what setup would I need to run both AC units?

Ill read through the suggested links starting tonight! Thanks for the info you all

To run both units concurrently, at home or otherwise, you'll want 50A service.

Just a quick way to think about the 50A/240V service: It has 4 wires compared to the 30A 120V service's 3 wires. 1 neutral and 1 ground (just like 30A) but 2 hot legs. The difference (voltage) between each of the hot legs and the neutral wire is 120V, and because of the way the North American power grid is set up and used, the difference between the 2 hot legs is 240v. So, a 240V RV plug is supplied on the electrical side just like any other 240V outlet, but the RV uses it a little differently than some appliances do. (Some appliances, internally, do similar things... they'll use just hot one leg to power the motor that turns the drum, but both to run the heating element in an electric dryer, for example.)

[Protagonist]

Originally Posted by DKB_SATX

To run both units concurrently, at home or otherwise, you'll want 50A service.

Just a quick way to think about the 50A/240V service: It has 4 wires compared to the 30A 120V service's 3 wires. 1 neutral and 1 ground (just like 30A) but 2 hot legs. The difference (voltage) between each of the hot legs and the neutral wire is 120V, and because of the way the North American power grid is set up and used, the difference between the 2 hot legs is 240v.

To run both rooftop a/c units, one would use one hot leg, neutral and ground, the other would use the other hot leg, neutral, and ground. Each hot leg should provide 25A, when you're laying out your new circuit breaker panel to decide which appliance to put on which hot leg.

[PharmGeek]

Originally Posted by dlb435

I work in the electrical power industry. I really can't suggest any books suitable for a little light reading. Most good electrical courses run about two years. Then there is the small matter that not all electricians are the same. We often refere to common electricians as "house wire" electricians. The limit of their knowledge was learning enough of the NEC to pass the test. (or getting a friend to get them all the answers)
My best suggestion is to find a good electrician that comes highly recommended.

To be clear, I am not trying to learn how to repair or install electric anything myself...

What I am looking for is reading or information on how an RV owner should conduct him/herself with regards to using electricity, monitoring it, and understanding it *enough* to get by reasonably well and not make obvious stupid mistakes and perhaps learn enough to do some routine checkups of different things.

[markdoane]

Originally Posted by Protagonist

To run both rooftop a/c units, one would use one hot leg, neutral and ground, the other would use the other hot leg, neutral, and ground. Each hot leg should provide 25A, when you're laying out your new circuit breaker panel to decide which appliance to put on which hot leg.

No. Each hot leg should provide 50 amps.

[PharmGeek]

oh boy, I think I will find and hire a highly qualified electrician that knows this stuff...my contractor responded via text just now when I told him it is 30am 120v needed, not 30amp 240v

his response:

"yeah, that is standard now. But hot water 20 amp. Ac. 15 Amp and oven 20, does not make sense!"

Not sure what his disconnect is exactly?

[Protagonist]

Originally Posted by PharmGeek

To be clear, I am not trying to learn how to repair or install electric anything myself...

What I am looking for is reading or information on how an RV owner should conduct him/herself with regards to using electricity, monitoring it, and understanding it *enough* to get by reasonably well and not make obvious stupid mistakes and perhaps learn enough to do some routine checkups of different things.

Then I repeat my recommendation from Post #9. I have that book in my own library; I bought it back when my plan was to buy a live-aboard boat. Now that I have an Airstream instead, there's still much useful information in it, and that's why I still have the book. RVIA standards have more in common with ABYC (American Boat & Yacht Council) than they do with NEC for household inside electrical or NFPA for exterior electrical. And let's face it, boats are where we got the term "shore power" to begin with!

Nigel Calder's books are written for folks with a fix-it-yourself handyman level of ability, not for professional electricians and mechanics, so you'll find a lot more of the "why" along with the "how."

[Protagonist]

Originally Posted by PharmGeek

oh boy, I think I will find and hire a highly qualified electrician that knows this stuff...my contractor responded via text just now when I told him it is 30am 120v needed, not 30amp 240v

his response:

"yeah, that is standard now. But hot water 20 amp. Ac. 15 Amp and oven 20, does not make sense!"

Not sure what his disconnect is exactly?

His disconnect is that he's thinking NEC when he should be thinking RVIA standards. National Electrical Code is not intended to apply to RVs.

[markdoane]

Originally Posted by Protagonist

His disconnect is that he's thinking NEC when he should be thinking RVIA standards. National Electrical Code is not intended to apply to RVs.

No. These issues are covered in NEC in detail. Just need to look in the right section. Duh.

[DKB_SATX]

Originally Posted by PharmGeek

oh boy, I think I will find and hire a highly qualified electrician that knows this stuff...my contractor responded via text just now when I told him it is 30am 120v needed, not 30amp 240v

his response:

"yeah, that is standard now. But hot water 20 amp. Ac. 15 Amp and oven 20, does not make sense!"

Not sure what his disconnect is exactly?

He doesn't know your water heater can run off propane? And that they still make gas ovens?

If you're going to buy a trailer that has 2 ACs from the factory, though, you'll have a 50A shore power cord and might as well install 50A 240V service with the correct socket, which would stop your contractor from worrying. As mentioned before, though, it pays to put a meter on a newly-installed socket before plugging anything expensive into it.

[Silverflames]

One way to think about it is like a sink.


30 amp service has 1 sink bowl, and 1 faucet (110 line), 1 drain ( common line), and the overflow drain (ground line). Now you pull water out as you need it.

50 amp Rv service is two of the above listed sink bowls with faucets sitting right next to each other, but they are sharing a drain line back out.

So you end up with one sink with 110 volts in it, and a second with 110 volts in it. You have two sinks to pull "water" out of.

Now this is the part I mess up, the Amps would be pipe size of the faucet. 30 amp would be 3/4" and the 25 Amp 25amp are 1/2" pipes. The larger the pipe more water or Amps you can get out. Please feel free to correct me if this is off.