Shore power - Page 3

Zephod_beeblebrox2 · 09-01-2015, 10:19 AM

Speaking of pink and blue I was idly looking at laptops online at Walmart. Their cheapest were $170 and available in pink or blue.

Now when Ubuntu comes out for them, they sound ideal for a mobile lifestyle.

crazycal · 09-01-2015, 10:31 AM

Quote:

Originally Posted by Zephod_beeblebrox2

Speaking of pink and blue I was idly looking at laptops online at Walmart. Their cheapest were $170 and available in pink or blue.

Now when Ubuntu comes out for them, they sound ideal for a mobile lifestyle.

I'm on a laptop right now using Ubuntu.

roach711 · 09-01-2015, 10:32 AM

A 15 amp breaker on a 30 amp (10 gauge) wire will be safe but will limit you to a total 15 amp draw. To get full power you need a 30 amp breaker on the incoming hot shore power wire.

You seem to be wandering around in the dark here. The danger you're risking is not to yourself so much because you installed the system and *presumably* know the limitations of it. But the next owner won't know that you made it up as you went along and may pay dearly for it. You call our system a "kludge" but that's exactly what you're building yourself.

I recently worked on a house where the owner had mis-wired a light switch on the neutral side instead of the hot side. The switch turned off the light but didn't kill power to the fixture. I found out about the problem the hard way.

My brother in law made up a "suicide cable" to hook up a generator to his house. It worked fine for him because he knew the danger but when his daughter tried to use the extension cord to power her vacuum she got shocked.

Please, learn how to do the job properly or have someone knowledgeable do it for you. The life you save may be your own.

crazycal · 09-01-2015, 10:38 AM

Quote:

Originally Posted by roach711

My brother in law made up a "suicide cable" to hook up a generator to his house. It worked fine for him because he knew the danger but when his daughter tried to use the extension cord to power her vacuum she got shocked.

Please, learn how to do the job properly or have someone knowledgeable do it for you. The life you save may be your own.

The first time I have heard of a suicide cable was this weekend at a presentation I attended.

Zephod_beeblebrox2 · 09-01-2015, 10:42 AM

Quote:

Originally Posted by crazycal

I'm on a laptop right now using Ubuntu.

Ubuntu has got so good now that I might go the Ubuntu route if the day comes that my macbook can't be resurrected.

I always see people fighting windows, steam coming out of their ears while proclaiming "but Windows is so good".

Zephod_beeblebrox2 · 09-01-2015, 10:52 AM

Quote:

Originally Posted by roach711

A 15 amp breaker on a 30 amp (10 gauge) wire will be safe but will limit you to a total 15 amp draw. To get full power you need a 30 amp breaker on the incoming hot shore power wire.

You seem to be wandering around in the dark here. The danger you're risking is not to yourself so much because you installed the system and *presumably* know the limitations of it. But the next owner won't know that you made it up as you went along and may pay dearly for it. You call our system a "kludge" but that's exactly what you're building yourself.

I recently worked on a house where the owner had mis-wired a light switch on the neutral side instead of the hot side. The switch turned off the light but didn't kill power to the fixture. I found out about the problem the hard way.

My brother in law made up a "suicide cable" to hook up a generator to his house. It worked fine for him because he knew the danger but when his daughter tried to use the extension cord to power her vacuum she got shocked.

Please, learn how to do the job properly or have someone knowledgeable do it for you. The life you save may be your own.

Oh, I'll write it all down on the inside of the breaker box cover.

The small breaker box I've seen takes two breakers. One can feed one leg and the other can feed the other. The cables combined can carry 60A. The big breaker box is rated at 70A. The socket going on the outside is rated at 50A.

The wire from the socket splits when it hits the first breaker box. This section uses 50A cable. The first breaker box has two 15A breakers.

One breaker feeds the left side of the sub panel. The other feeds the right side. The cable for each side is 30A.

Advantage... When I'm on a 30A circuit, both breakers in the mini box can be on. On a 15A circuit, I turn one off and just have two active sockets.

All perfectly safe. Of course , as I said, a schematic will be drawn on the inside of the big breaker box door - not so much for the next owner but more for me because I don't remember everything!

bansil · 09-01-2015, 10:53 AM

Quote:

Originally Posted by crazycal

The first time I have heard of a suicide cable was this weekend at a presentation I attended.

I made one, so that shows you didn't read my build thread

I even put a warning label up

bansil · 09-01-2015, 10:55 AM

labeling is a good thing

from my build thread
so here she is bare

the neutrals and grounds where easy

next needed to know which hot went were so I could "load" the 50 amp side

I salvaged the rear door buzzer

,a fuse,couple alligator clips and a "power source, 12 transformer"

I made a quick circuit checker, hot goes thru fuse to wire at plug (i used an old plug with pig tail just to plug into sockets)

then when you touch the (-) of the power source it will buzz alarm....easy peezee

done !!!!!

it's wired so if I have 50 amp I have 2 sockets on a seperate "leg" front ac or heater"

I "roughed in" another panel and it will be stored away in the bus...just incase...still very weird

I also decided to do this:

just incase....dunno...just incase

Zephod_beeblebrox2 · 09-01-2015, 10:59 AM

Your pics aren't showing

crazycal · 09-01-2015, 12:20 PM

Quote:

Originally Posted by Zephod_beeblebrox2

Your pics aren't showing

I see them. Maybe you shoulld switch to Ubuntu now..

Zephod_beeblebrox2 · 09-01-2015, 12:48 PM

Quote:

Originally Posted by crazycal

I see them. Maybe you shoulld switch to Ubuntu now..

Yeah, they're showing now. They weren't earlier

Scooternj · 09-01-2015, 01:26 PM

Quote:

Originally Posted by crazycal

I see them. Maybe you shoulld switch to Ubuntu now..

I see them

roach711 · 09-01-2015, 05:49 PM

One....last....try to talk some sense here.

Zaphod, the receptacle on the outside of your bus should be a proper RV male receptacle, not a female. Your female receptacle requires that you build an extension cord with two male ends (a suicide cord). This is a big problem.

Imagine that someone is helping you pack up before the drive home. She (maybe your wife) unplugs the bus end of the extension cord first and begins rolling up the cord. The end she just unplugged is still hot and she touches the male prongs. Imagine the fun things she'll say to you if she survives.

Imagine that some kids (maybe yours) are playing around the back of your bus and one trips on the cord, and since it's not a twist lock plug it unplugs from the bus receptacle and since it's a male plug it's easy to touch the hot prongs. Maybe one of them picks it up, touches the male prongs and gets a shock, just like my niece did. Maybe the grass is wet and both kids are bare footed (and therefore very well grounded). If those male prongs touch the wet grass both kids (as well as anyone else close by standing on that same grass) are going to be badly shocked and quite possibly killed. This is not just theoretical; it happens way too often in real life.

Lets talk about the American legal system. If one of those kids dies and the parent's lawyers find this thread proving you were told your system was dangerous and went ahead anyway you'll be charged with negligent homicide.

Now tell me, would you prefer to take the time and do it right or would it be more fun to live your life knowing someone died because you thought you knew better than everyone else?

Zephod_beeblebrox2 · 09-01-2015, 06:06 PM

Hmm.. Hadn't considered the exposed live wires. I have thought two 15a standard cords would be cheaper than a single 30 by a large margin.

crazycal · 09-01-2015, 08:57 PM

Quote:

Originally Posted by Zephod_beeblebrox2

Hmm.. Hadn't considered the exposed live wires. I have thought two 15a standard cords would be cheaper than a single 30 by a large margin.

Are you trying to prove Darwin's theory?

Redbear · 09-01-2015, 09:45 PM

Quote:

Originally Posted by bansil

keep this in mind

50 amp service is actually 2 110V lines coming in, one will have 25 amps available to use and the other will have 25 amps available (these numbers are for demonstration) . . .

Wrong! The "50-amp" 4-pin 120/240 volt RV outlet has a full 50 amps available on each hot leg. If you are using only 120-volt appliances, and you wire the bus to carefully divide the loads half on one hot leg to neutral, and half on the other leg to neutral, you have a total of 100 amps available at 120 volts. Either way, there are 12,000 watts available, either 50A x 240V or 100A x 120V, or some lesser combination of the two.

If the campground is mis-wired, and both hot pins are on the same supply leg, then you have zero volts at the 240-volt appliances, 50 amps on each hot leg, and 100 amps on the overloaded neutral wire rated for only 50 amps.

If both the outlet and bus are correctly wired for 120/240, then the neutral only carries the difference in current between the draws of the two hot legs. If you have a 1200 watt, 120-volt heater runing on one hot leg (10 amps), and a 60-watt light bulb running on the other (1/2 amp), then 1/2 amp from the heater continues through the light bulb to the opposite leg, and the 9-1/2 amps difference current from the heater returns through the neutral.

The 30 amp, 120-volt only RV outlet is only capable of 3600 watts. It has one hot, the neutral, and the safety ground.

The 3-prong outlet in ZB's photos may be an older 120/240-volt cookstove plug with no safety ground. In Grandpa's day, installers ran a separate safety ground wire from the case of an appliance to a nearby metal water pipe. It instead may be a 240-volt only cord with two hots and a safety ground, and no neutral. If so, there would be no 120-volts available for New World appliances.

Back in the old country, there is no neutral, and no 120-volt half voltage available. There are only two hots. That's why all plugs have fuses in them on both wires, and insulation on the back of the pins so you can't have the plug in far enough to connect to the mains and still have metal to touch on the pins of a half plugged in cord.

Zephod_beeblebrox2 · 09-01-2015, 09:51 PM

I'm looking at this
http://www.electricalmaterialscompan...etered-370.jpg
Is this standard at most RV sites?

I see two sockets that *look* like 110v 15A sockets on the bottom right. Am I correct?

Redbear · 09-01-2015, 10:01 PM

The one on the left is a 4-pin, 120/240 volt 50-amp socket, 12,000 watts.
The one in the middle is a 3-pin, 120 volt 30-amp socket, 3600 watts. Ignore the hole in the middle.
The two on the right accept both 15 amp (blades parallel) or 20-amp (neutral turned 90°) cords, 2400 watts between the two.

Each outlet has its own breaker above. The 240-volt breaker is two lines strapped so both hot wires trip off together.

Zephod_beeblebrox2 · 09-01-2015, 10:09 PM

Are the 15 amp sockets common in paiurs? Just thinking 15a cirds are cheaper than 30a cords

Redbear · 09-01-2015, 10:23 PM

Yes, most 15-amp and 20-amp receptacles are dual.
*BUT*
The 20-amp is the rating for the one cable feeding both outlets.

You cannot safely draw 30 or 40 amps by plugging in two cords into opposite halves of a dual outlet. The draw from the two cords must add up to the outlet rating.

It is a false economy to skimp on extension cords, especially on long runs. All wiring has some resistance, and resistance when current is drawn means heat is generated and power is lost.

My old camper does not have much draw, so I removed the heavy #10 cord with the 30-amp plug and wired in a replacement #12 wire good for 20 amps. Though there are a couple of AC outlets, the cord really only runs the converter to charge the battery, and run the 12-volt lights and 12-volt furnace blowers.

If you go to the hardware store or home center, a lot of the bargain outdoor cords have only #16 wire, which won't even handle 15 amps well. Pick through to find (or build) a #12 or at least #14 cord.

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