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**richard5933** · 10-07-2022, 06:34 AM

That box will give you two 120v circuits, but it won't give you the 30-amp main breaker. With two 20-amp circuits this setup would be able to try and pull 40 amps from the pedestal.

Two potential problems here...

1) It's inconvenient to not have a main breaker inside the trailer. Nice to have a way to quickly shut off all power with a single breaker, and even nicer to not have to go out to the pedestal if you overload things.

2) More importantly, it leaves everything between this box and the pedestal unprotected against power draws over 30-amps.

Jcondon · 10-07-2022, 07:28 AM

Quote:

Originally Posted by Serf27

Hmm, maybe I’m using the 120v term incorrectly.
I wanted the 30amp box but there was only the 70amp box, I got that and 2 20amp breakers.
I thought if it was rated for up to 70amps, then it should be fine with 2 20amp breakers.

Here is a photo of the box.
Based on a video I’ve seen a few times, this is how it is wired.

The box has 2 spaces for breakers.
The 20amp breakers go in each space.
The hot wire from shore power goes to 1 breaker and then a jumper wire is used to power the other breaker.

The neutral wire from shore power goes to a neutral bar inside the breaker box.

The ground wire from shore power goes to a ground bar on the frame.

Those 3 wires from shore power will go to a connector that is screwed into the side of the box housing all electrical components. That connector will be used to actually connect a cord to shore power.

Now here’s the wiring leaving the breaker box, or the output side.

Hot on 20 amp breaker goes to one GFCI receptacle
Neutral goes to GFCI
Ground goes to GFCI
From this same receptacle, the 3 wires are ran to a second receptacle and then to a third receptacle.

From the 2nd 20 breaker, hot wire goes to another GFCI.
Neutral goes to GFCI
Ground goes to GFCI
Those 3 wires lead to a second receptacle and that’s it.

That’s how I understood that it is to be wired up.
I added the GFCI last minute for the kitchen and an exterior outlet.

Is it correct or wrong?

Thanks.

A normal shore power cord is a 120 volt 30 amp. All camping places will have access to one. It is plugged into a 30 amp receptacle at the site. This hot wire would land on your 30 amp main breaker inside the panel. A jumper on the lugs would connect both phases together. Then you can plug in your 20 amp breaker in the other space to connect your loads. Square D makes a dual breaker that will fit in the remaining slot giving you two circuits with a 30 amp main breaker.

Jcondon · 10-07-2022, 07:33 AM

Quote:

Originally Posted by Serf27

I have 5 15 amp receptacles and 2 20 amp breakers.
The only box available was a 70amp breaker box.

70 amp is just the rating of the buss. Square D has a minimum amperage of 70 amps. Carry on.

Wazbro · 10-07-2022, 09:48 AM

That box looks like it is designed to be a shore power hookup (the place you plug your trailer into) not a distribution box in your trailer. Like this.
https://www.homedepot.com/p/Midwest-...41CP/202307106
One like this would be better.
https://www.homedepot.com/p/Square-D...190554#overlay

Jcondon · 10-07-2022, 11:07 AM

Quote:

Originally Posted by Wazbro

That box looks like it is designed to be a shore power hookup (the place you plug your trailer into) not a distribution box in your trailer. Like this.
https://www.homedepot.com/p/Midwest-...41CP/202307106
One like this would be better.
https://www.homedepot.com/p/Square-D...190554#overlay

This is a 70 amp 2 space distribution panel so it is fine for what he is doing. More spaces would be nice though.

**richard5933** · 10-07-2022, 11:14 AM

Quote:

Originally Posted by Jcondon

This is a 70 amp 2 space distribution panel so it is fine for what he is doing. More spaces would be nice though.

With a 2-space panel there would be no way to have a 30-amp main breaker and still have two individual circuits, unless I'm missing something.

Jcondon · 10-07-2022, 01:16 PM

Quote:

Originally Posted by richard5933

With a 2-space panel there would be no way to have a 30-amp main breaker and still have two individual circuits, unless I'm missing something.

You are missing something.

Jcondon · 10-07-2022, 01:35 PM

Quote:

Originally Posted by Jcondon

You are missing something.

This! Square D HOM Tandem! You can get 20/20 and 20/30 also. This can give you a 30 amp main with three branch breakers out of that very small panel.

**richard5933** · 10-07-2022, 01:43 PM

Quote:

Originally Posted by Jcondon

This! Square D HOM Tandem!

Ok. Tnx.

Serf27 · 10-07-2022, 01:51 PM

I thought the purpose of the breakers was to switch off in the breaker box if something tries to pull too much power. Even then, I thought the GFCI would switch off before it got to the breaker.
A bit confused now.

I don’t have much space for for a bigger box and don’t have a lot of outlets installed either.

So I can still use this box?

With the 2 space box, I would use 1 30amp breaker in one space and the other space would be the 2in1 breaker?
Or how would I do this.

This is the video where I got all this info from.
The breaker box wiring starts at minute 22:50.
https://youtu.be/ckud3-kf8vw

Thanks.

Jcondon · 10-07-2022, 01:55 PM

Quote:

Originally Posted by Serf27

I thought the purpose of the breakers was to switch off in the breaker box if something tries to pull too much power. Even then, I thought the GFCI would switch off before it got to the breaker.
A bit confused now.

I don’t have much space for for a bigger box and don’t have a lot of outlets installed either.

So I can still use this box?

With the 2 space box, I would use 1 30amp breaker in one space and the other space would be the 2in1 breaker?
Or how would I do this.

This is the video where I got all this info from.
The breaker box wiring starts at minute 22:50.
https://youtu.be/ckud3-kf8vw

Thanks.

Your panel is fine. Fill it with Tandems. I posted a photo above.

Serf27 · 10-07-2022, 02:09 PM

So I get 1 20/20 tandem breaker and 1 20/30 tandem breaker?
The 30amp breaker will cause the GFCI and breakers to switch off if over loaded?

I do not see a 20/30 Square D in stock at the store.
I do see 15/15 and 15/20.

https://www.homedepot.com/p/Square-D...20CP/202353308

Jcondon · 10-07-2022, 03:55 PM

Quote:

Originally Posted by Serf27

So I get 1 20/20 tandem breaker and 1 20/30 tandem breaker?
The 30amp breaker will cause the GFCI and breakers to switch off if over loaded?

I do not see a 20/30 Square D in stock at the store.
I do see 15/15 and 15/20.

https://www.homedepot.com/p/Square-D...20CP/202353308

Use a full size single pole 30 as the main breaker which backfeeds the buss. Then a 20/20 tandem to get your two circuits. This post is the exact reason I started building prewired AC/DC distribution panels. These simplify the whole process and all the fusing is correct.

Jcondon · 10-07-2022, 04:21 PM

Quote:

Originally Posted by Serf27

So I get 1 20/20 tandem breaker and 1 20/30 tandem breaker?
The 30amp breaker will cause the GFCI and breakers to switch off if over loaded?

I do not see a 20/30 Square D in stock at the store.
I do see 15/15 and 15/20.

https://www.homedepot.com/p/Square-D...20CP/202353308

If you need three branch circuit breakers the 30/20 is available on Amazon.

Serf27 · 10-07-2022, 04:59 PM

Quote:

Originally Posted by Jcondon

Use a full size single pole 30 as the main breaker which backfeeds the buss. Then a 20/20 tandem to get your two circuits. This post is the exact reason I started building prewired AC/DC distribution panels. These simplify the whole process and all the fusing is correct.

Oh I see what you mean.
A 30 amp breaker in 1 spot of the breaker.
Then a 20/20 breaker in the second spot.
The hot wire input from shore power goes to the 30amp breaker and then the jumper wire connects both breakers together.

From the 20/20 breaker, run the hit wires to outlets?
On the single 30amp breaker, nothing is connected to the hot output side, right?

I don’t need the “3 branch” I was confused and thought it was needed.

Is 8 gauge fine to feed the breaker box from the 30 amp connector that goes to shore power? Or should I get 6 gauge?
This wire will only be about 1.5ft long between the breaker box and the connector.

Thanks.

Jcondon · 10-07-2022, 05:27 PM

Quote:

Originally Posted by Serf27

Oh I see what you mean.
A 30 amp breaker in 1 spot of the breaker.
Then a 20/20 breaker in the second spot.
The hot wire input from shore power goes to the 30amp breaker and then the jumper wire connects both breakers together.

From the 20/20 breaker, run the hit wires to outlets?
On the single 30amp breaker, nothing is connected to the hot output side, right?

I don’t need the “3 branch” I was confused and thought it was needed.

Is 8 gauge fine to feed the breaker box from the 30 amp connector that goes to shore power? Or should I get 6 gauge?
This wire will only be about 1.5ft long between the breaker box and the connector.

Thanks.

You are getting closer. The shore power cord for 30 amp will be 10/3 SOW cord. This should land on a cord grip into your breaker panel. The black hot wire lands on the screw terminal of the 30 amp breaker. This backfeeds the buss making one buss hot when plugged in and the 30 amp breaker is on. Then a #10 black jumper wire connects one buss to the other using the terminals. Now both busses are hot when the 30 amp breaker is on. Then the 20/20 tandem plugs in and now you have 2 20 amp breakers for your outlets. I can not make it any clearer unless I come over.

Jcondon · 10-07-2022, 05:58 PM

Quote:

Originally Posted by Serf27

Oh I see what you mean.
A 30 amp breaker in 1 spot of the breaker.
Then a 20/20 breaker in the second spot.
The hot wire input from shore power goes to the 30amp breaker and then the jumper wire connects both breakers together.

From the 20/20 breaker, run the hit wires to outlets?
On the single 30amp breaker, nothing is connected to the hot output side, right?

I don’t need the “3 branch” I was confused and thought it was needed.

Is 8 gauge fine to feed the breaker box from the 30 amp connector that goes to shore power? Or should I get 6 gauge?
This wire will only be about 1.5ft long between the breaker box and the connector.

Thanks.

I think you are using a Marinco 30 amp shore power inlet? With a plug in shore power cord? If so, #10 wire from the connector to the panel is fine. I would use 10/2 MC Cable and land it with a speed lock connector in the breaker panel. Confirm this is what you mean?

Serf27 · 10-07-2022, 06:50 PM

Ok thanks. I was just making sure the wiring was correct.

Yes, I am talking about the wire that will connects the breaker box to the inlet connector. The inlet connect is the one where an extension cord is used to connect to the pedestal/shore power.

I asked for SOW at the store and Al they had was 10/3 and said SOW wouldn’t work… The worker said to use 12/2 Romex and I said that it would be to small.
So I didn’t get any wire.
Should I get the 10/3 Or 8gauge?

The old electrical system was a mess so I needed a new connector/plug.
This is the connector I bought.

Jcondon · 10-07-2022, 07:11 PM

Quote:

Originally Posted by Serf27

Ok thanks. I was just making sure the wiring was correct.

Yes, I am talking about the wire that will connects the breaker box to the inlet connector. The inlet connect is the one where an extension cord is used to connect to the pedestal/shore power.

I asked for SOW at the store and Al they had was 10/3 and said SOW wouldn’t work… The worker said to use 12/2 Romex and I said that it would be to small.
So I didn’t get any wire.
Should I get the 10/3 Or 8gauge?

The old electrical system was a mess so I needed a new connector/plug.
This is the connector I bought.

That is the correct receptacle for your shore power outlet. Just so we are on the same page post a photo of your shore power inlet on the outside of your trailer. A 30 amp circuit does need #10 wire but SOW should not be installed inside. 10\2 MC or Romex goes inside.

Serf27 · 10-07-2022, 07:29 PM

Quote:

Originally Posted by Jcondon

That is the correct receptacle for your shore power outlet. Just so we are on the same page post a photo of your shore power inlet on the outside of your trailer. A 30 amp circuit does need #10 wire but SOW should not be installed inside. 10\2 MC or Romex goes inside.

I don’t have one. The old system was some type of small converter or breaker box and had a standard small extension cord on it.

I still need this piece:
Shore Power Inlet 125V 30 Amp RV Adapter Great Replacement for Trailer RV Camper Van NEMA L5-30R - 30 Amp RV Receptacle Twist Lock Connector with 3 Stainless Steel Pins and Screws https://a.co/d/7cmgb0f

I also need the wire that goes between that piece and the breaker box so I can run that wire to the breaker box and just install the connector when I get one.
Inside the trailer, I have 12/2 Romex for the receptacles.