Putting 240V into a trailer

[AntonLargiader]

My work neighbor wants to outfit an older 2-horse trailer as a mobile coffee stand and asked for my help. It will either be plugged into shore power or connected to a generator.

The equipment ratings he gave me are as follows:
- espresso machine 21A @ 220V
- grinder 7.3A @ 110V
- fridge 4A @ 115V
- grinder 2.1A @ 115V
- water pump 0.4A @ 115V

Also there will be some LED lights and convenience receps for a radio or whatever. I’d use all GFCI receps.

I’m thinking a small 4-space 240V panel with a 30A double breaker for the espresso machine and two 20A circuits would do the trick. I’d use 25 feet of 10/4 S-cord with a 30A twist-lock connector to connect to shore power or generator. It’s an all-metal trailer and I assume I would ground the cord to the trailer.

For a generator, looking at some on the web it looks like in the 5500W range you basically pay for quietness, starting with the Honda EU7700is and getting louder/cheaper from there.

I don’t see any reason to tie the 12V system to this. There will be an overhead light and maybe an exterior one or two on the 12V system but when the trailer is in use there will always be external AC power.

Is there anything special I need to take into account with the wiring, grounding, or anything else? We think the cord will be stowed in a box on the tongue, connected to a small panel on the inside front. From there power would go up to the ceiling and then down the walls to the receps. Not sure how the espresso machine is connected yet.

 

[theoldwizard1]

Use the RV industry standard for 240V 50A service. NEMA (non locking) 14-50. SJOOW 10 gauge is fine.

Yes, you will need an adapter for use with the Honda generator.

 

[wyliesdiesels]

30a will not be enough if you have the espresso machine, large grinder and fridge running at the same time.

I would go with more ampacity.

 

[wyliesdiesels]

Use the RV industry standard for 240V 50A service. NEMA (non locking) 14-50. SJOOW 10 gauge is fine.

Yes, you will need an adapter for use with the Honda generator.

#10 for 50a?

Aww no

 

[AntonLargiader]

I’d thought about a 14-50 instead, but they said the only place they plug in will be a spot where they install their own receptacle. Installing a 14-50 would be fine, too.

 

[outdoorspace]

I used this for my generator hook up. It's the standard twist lock for RVs and rated for 50A.

https://www.amazon.com/dp/B0716JHHF3/?tag=atomicindus08-20

 

[AntonLargiader]

30a will not be enough if you have the espresso machine, large grinder and fridge running at the same time.

Can do 50A cord but the generator probably won’t. How is 30A @ 240V not enough, if the big grinder and the fridge are on different legs? It’s close but these are not continuous loads.

 

[mike93lx]

Aside from the electrical, i have to say, converting a mobile horse bathroom into something that food will be served from is unappealing at best to me.

Those are some significant power draws that are going to require a significant generator. I would try to meter actual draws, especially on the espresso machine, first

 

[checkthisout]

After the build is done, won't it have to be certified/inspected for electrical, sanitation and food service by whoever does that in your state/county etc?

 

[AntonLargiader]

Those are some significant power draws that are going to require a significant generator. I would try to meter actual draws, especially on the espresso machine, first

We will. It'll be used on shore power for a while before it has to be on a generator. It would be great if it stays within reach of a 5500W unit. Bigger than that, they all get really loud. The 7000 has a 23/29A rating, and I think the heaviest load on the espresso machine will be while it's heating up... before the grinders are needed.

After the build is done, won't it have to be certified/inspected for electrical, sanitation and food service by whoever does that in your state/county etc?

Maybe for the food service stuff. Don't know.

 

[wyliesdiesels]

Can do 50A cord but the generator probably won’t. How is 30A @ 240V not enough, if the big grinder and the fridge are on different legs? It’s close but these are not continuous loads.

sorry, i added it up wrong.

thats what i get for replying when im half awake

 

[Falcon67]

The EU7000is we have uses an L14-30 twist lock socket. The 10 gauge cord from the trailer factory uses a 4 prong 50A style plug, so we use a short adapter from TSC on the end of the cord. If the espresso is really 21A @ 240v you'll need to budget power in the trailer. The 7000 is a great generator, very quiet and easy to maintain. It will vary speed based on load so when on a light load it's REAL quiet. It's a gas sipper too. We were running 15 gallons a weekend on a Friday night, Saturday + Sunday race with our old (loud) 6500 Champion. This last weekend I put just about 6 gallons in the Honda.

The Amazon link to the RV adapter is the same one used on our trailer. I would use an inverter/charger to keep a house battery up because there will be times he may need to see or do some other choirs without having to start the genny.

Also note that the EU7000is is a heavy bastage. About 400 lbs full of fuel. Depending on the tow vehicle and the length of the tongue, you might consider mounting said generator to the trailer tongue. You ain't gonna hoof that SOB up in the back of a pickup without a engine hoist.

 

[AntonLargiader]

Thanks for that info. 400 pounds, wow. It turns out there is plenty of time before they have to think about a generator so for now I am just making a shore power connection. They may be able to rent a 7000 when they need one.

They are checking on the available receptacle at the intended venue, and they will also get started on installing the appliances.

The shopping list looks like:
- 30A inlet box like this
- 30A cord
- Compact breaker panl (4 to 6 slots preferably) like this
- boxes, wire, conduit, receps. Considering PVC.

Question about the load center: this is a small trailer and they're working with liquids. Is there a sealed load center I can buy? I haven't seen anything like that. Even the outdoor types aren't sealed.

 

[nadogail]

"Also note that the EU7000is is a heavy bastage. About 400 lbs full of fuel. Depending on the tow vehicle and the length of the tongue, you might consider mounting said generator to the trailer tongue. You ain't gonna hoof that SOB up in the back of a pickup without a engine hoist."
My generator is on a 4 wheel dolly and I use a cable come along to winch it up a ramp into my van.
The ramp is welded up from angle iron and the wheels fit inside tracks on the ramp.

Ratchet straps keep the generator in place in the van.

 

[TRWham]

If that espresso maker is a European 220V model, remember that the heaters will draw a good bit more (like 20% more) wattage than the rating when running on 240V (square of current times resistance). That will be 5,500 Watts by itself if my math is right.

 

[mm08822]

Thanks for that info. 400 pounds, wow. It turns out there is plenty of time before they have to think about a generator so for now I am just making a shore power connection. They may be able to rent a 7000 when they need one.

They are checking on the available receptacle at the intended venue, and they will also get started on installing the appliances.

The shopping list looks like:
- 30A inlet box like this
- 30A cord
- Compact breaker panl (4 to 6 slots preferably) like this
- boxes, wire, conduit, receps. Considering PVC.

Question about the load center: this is a small trailer and they're working with liquids. Is there a sealed load center I can buy? I haven't seen anything like that. Even the outdoor types aren't sealed.

You can get a Nema 3R rated panel in 8/16 ckt or 6/12 ckt such as:

QO816L100RBCP or QO612L100RBCP

At least add a few more ckts capability for future.

 

[mm08822]

If that espresso maker is a European 220V model, remember that the heaters will draw a good bit more (like 20% more) wattage than the rating when running on 240V (square of current times resistance). That will be 5,500 Watts by itself if my math is right.

Very possible! Your math is right.

 

[AntonLargiader]

If that espresso maker is a European 220V model, remember that the heaters will draw a good bit more (like 20% more) wattage than the rating when running on 240V (square of current times resistance). That will be 5,500 Watts by itself if my math is right.

I looked at it yesterday and it says 4500W and the 208~240V and 60Hz boxes are marked. So it appears to have been at least built for the US market. I don't know if they found the 21A number somewhere else or derived it themselves.

You can get a Nema 3R rated panel in 8/16 ckt or 6/12 ckt such as:
QO816L100RBCP or QO612L100RBCP
At least add a few more ckts capability for future.

I'll try to go with six. I've seen those, and the cost is pretty low, but I was wondering if there was something more industrial/plastic/sealed than that. Like the QO24L60NRNM but with more slots. The current ideal mounting spot is pretty low. However, it could go higher with a bit more wiring.

 

[Falcon67]

My generator is on a 4 wheel dolly and I use a cable come along to winch it up a ramp into my van.
The ramp is welded up from angle iron and the wheels fit inside tracks on the ramp.

Ratchet straps keep the generator in place in the van.

I can wheel the EU7000 into our race trailer. It's heavy but it rolls easy enough. Yes, it's secured to the floor with a heavy duty strap. The floor tracks are secured to the under floor beams. I don't use any wall type tie downs, I secure rings to the edge of the floor with the screws/bolts going into the perimeter steel. But we carry a bit of heavy stuff - race car, generator, quad, tool box, etc.

 

[tyme2par4]

Is there anything special I need to take into account with the wiring, grounding, or anything else? We think the cord will be stowed in a box on the tongue, connected to a small panel on the inside front. From there power would go up to the ceiling and then down the walls to the receps. Not sure how the espresso machine is connected yet.

I would just note that trailers aren't built to be outfitted with electricity. So one thing you will need to be sure of is that anything metal, anywhere near a wire is well grounded. Don't just assume the frame is grounded if you connect to it at one point. Metal parts that are painted before being bolted together aren't going to have a good connection.
Trailers flex and bounce on the road, and it could easily lead to a chaffed or pinched wire that could cause parts of the trailer to become live.

 

[wyliesdiesels]

I looked at it yesterday and it says 4500W and the 208~240V and 60Hz boxes are marked. So it appears to have been at least built for the US market. I don't know if they found the 21A number somewhere else or derived it themselves.



I'll try to go with six. I've seen those, and the cost is pretty low, but I was wondering if there was something more industrial/plastic/sealed than that. Like the QO24L60NRNM but with more slots. The current ideal mounting spot is pretty low. However, it could go higher with a bit more wiring.

4500w / 208v = ~21.63a

 

[AntonLargiader]

Breaking news - Health Department wants hot water in there. Options are to go with propane and get by with a 30A generator, or go electric and potentially need 40A. Will work on that tomorrow with them.

Today does have a question though: which portable generators in this size (5500W to 7500W) are junk and which are good? Honda is always 5x the cost of the cheap ones, but much quieter up to 5500W. After that they are similar in noise to the cheapos.

 

[AntonLargiader]

Looks like we will go electric H20 for cheap and easy compliance, and bump up to 50A. Once they have operated it for a while we can see what the actual usage profile is and see if we can still squeeze into a 30A generator. Now I'll put together a bill of materials.

 

[AntonLargiader]

Just to close the loop on this, the project is changing and is on hold at the moment, which is fine with me. I don't need to liability of someone getting shocked when they touch the all-metal trailer because something went wrong or I didn't ground something the right way.

I will wire the 12V stuff and then my part is done.

 

[Falcon67]

IMHO the Honda units are worth the $. They can/will save you fuel in the long run and the noise level is very good. They also put clean power which will help any electronics you might chose to use. We have used Champion generators and the work very well, but are not quiet. The noise WILL get on your nerves after some time period. Note that our trailer has a bath package that includes a 6 gallon water heater. And we don't need 50A to run the thing. 15K BTU A/C, 700w microwave (that pulls as much as 10A heating water), dorm size fridge, air compressor, water heater, fan, computers, battery charger, lights - all run fine on 5500w without any power budget.

Ours is a 6 gallon WaiWella. Good unit, also includes a winter mode to keep the tank from freezing while using minimal power.

 

[sberry]

Just to close the loop on this, the project is changing and is on hold at the moment, which is fine with me. I don't need to liability of someone getting shocked when they touch the all-metal trailer because something went wrong or I didn't ground something the right way.

I will wire the 12V stuff and then my part is done.

We all should be learning to ground something properly.
I was at a local carny and almost called the fire marshal. A 4 wire feed to a 3 wire trailer and no ground connected, plug and recept sitting on top of a bucket to keep it out of a puddle in the rain. Told my mother and kids, stay away from that trailer.
I have seen a couple of these type trailers all boogered up, mostly mom and pop schemes. The carny owned stuff is pretty good.

 

[wyliesdiesels]

Geez

Shouldve told someone.