DIY 50 amp to 20 amp pigtail

[KnowNuthin]

I want to plug my tractors block heater into our 50 amp RV service for the upcoming winter months…

Our panel has 1 - 50 amp and 2 - 20 amp breakers… both 20 services are taken and currently used year round… (chicken heat lamps, water bowl heaters etc.)…

What I’m envisioning is a 50 amp plug with a 3 wire pigtail connected to the common, neutral and one hot leg… leaving the second hot leg vacant…

This would give me 120v 50 amp at the pigtail end… no?

This would be used STRICTLY for a 600 watt engine block heater…

Is this a bad, terrible or workable idea?

[enblethen]

This looks like a better product then building one. At least it has some overcurrent protection.
Surieen Adapter

[pianotuna]

CharlesinGA,


Nice find!

[wa8yxm]

time2roll wrote:

CharlesinGA wrote:
For the price, you cannot buy the stuff to make this and it is EXACTLY what the OP needs.

I was about to recommend a $10 power strip from WM with a breaker but this item is perfect. Even looks semi weather resistant.

Fully agree. Exactly what he's looking for and you can't beat the price unless you have a very well stocked "Spares" box. The plug alone is close to the 10 dollar price.

[time2roll]

CharlesinGA wrote:
For the price, you cannot buy the stuff to make this and it is EXACTLY what the OP needs.

I was about to recommend a $10 power strip from WM with a breaker but this item is perfect. Even looks semi weather resistant.

[CharlesinGA]

toedtoes wrote:
Would this work for you? It has a built in circuit breaker for added protection:
50amp to 4x 15/20amp adapter

For the price, you cannot buy the stuff to make this and it is EXACTLY what the OP needs.



Charles

[Cummins12V98]

KnowNuthin wrote:

Cummins12V98 wrote:


I advise 12GA wire and 20A breaker.

Our barn sub-panel is supplied by a 50@ 2-pole breaker in our main house panel… the circuits original purpose was to have a 240v, 50@ welder outlet in the garage.. I had an electrician repurpose that service to our 50@ RV plug in the barn (no longer a 240v outlet in the garage)…

I currently have one 50@ and 2-20@ breakers in the sub-panel… when we plug in the RV we shut off the. 20a breakers and vice-versa…

The spousal unit is an electrical engineer and as such has assured me EVERYTHING electrical is underrated… I.e. we have more than 50@ going into the barn panel and each of the breakers will handle more than their rated capacity (but will trip in the event of an short/overload)… at least that’s what I heard… when she gets going I understand about every third word, the rest is electrical-eze…

Chances are very good I won’t ever run each of the circuits up to their rated capacity… but I’m the worrying kind…

My intention was to replace one of the existing 20a breakers with a 15a then add a second 15a breaker…. Which would give me 20a + 15a + 15a = 50a (plus the dedicated 50a RV outlet)

Yes? No? Other suggestions?

You actually have two 50A circuits available as 100A total capacity. Add another 20A and forget it.

[wnjj]

ktmrfs wrote:

wnjj wrote:
The breakers in the sub panel do not have to add up to the capacity of the supply. Look at your house main panel as an example to see far more than 200A or whatever size panel you have.

Consider too that 50A at 240V is equivalent to 100A at 120V. So you can put several 20A breakers in there and not have an issue even if all were maxed out.

I also see no reason to turn breakers on and off as use them. The 50A breaker at the house will prevent you from overloading the supply.

On final nit pick: You still have a 240V plug in your barn if the RV plug is a 50A one. The RV just uses it as two 50A , 120V circuits.

50A at 240V CAN be UP TO 100A at 120, but could be less, depends on how the two legs are loaded. Each leg is protected to 50A, either leg goes over 50A and a properly installed 50A/240V breaker will trip both legs.

Yeah I left that pesky detail out about balancing them across the legs. As you fill slots in the panel they will alternate so you have to go out of your way to load them all on one side, but your point is taken.

[ktmrfs]

wnjj wrote:
The breakers in the sub panel do not have to add up to the capacity of the supply. Look at your house main panel as an example to see far more than 200A or whatever size panel you have.

Consider too that 50A at 240V is equivalent to 100A at 120V. So you can put several 20A breakers in there and not have an issue even if all were maxed out.

I also see no reason to turn breakers on and off as use them. The 50A breaker at the house will prevent you from overloading the supply.

On final nit pick: You still have a 240V plug in your barn if the RV plug is a 50A one. The RV just uses it as two 50A , 120V circuits.

50A at 240V CAN be UP TO 100A at 120, but could be less, depends on how the two legs are loaded. Each leg is protected to 50A, either leg goes over 50A and a properly installed 50A/240V breaker will trip both legs.

[wnjj]

The breakers in the sub panel do not have to add up to the capacity of the supply. Look at your house main panel as an example to see far more than 200A or whatever size panel you have.

Consider too that 50A at 240V is equivalent to 100A at 120V. So you can put several 20A breakers in there and not have an issue even if all were maxed out.

I also see no reason to turn breakers on and off as use them. The 50A breaker at the house will prevent you from overloading the supply.

On final nit pick: You still have a 240V plug in your barn if the RV plug is a 50A one. The RV just uses it as two 50A , 120V circuits.

[KnowNuthin]

Cummins12V98 wrote:


I advise 12GA wire and 20A breaker.

Our barn sub-panel is supplied by a 50@ 2-pole breaker in our main house panel… the circuits original purpose was to have a 240v, 50@ welder outlet in the garage.. I had an electrician repurpose that service to our 50@ RV plug in the barn (no longer a 240v outlet in the garage)…

I currently have one 50@ and 2-20@ breakers in the sub-panel… when we plug in the RV we shut off the. 20a breakers and vice-versa…

The spousal unit is an electrical engineer and as such has assured me EVERYTHING electrical is underrated… I.e. we have more than 50@ going into the barn panel and each of the breakers will handle more than their rated capacity (but will trip in the event of an short/overload)… at least that’s what I heard… when she gets going I understand about every third word, the rest is electrical-eze…

Chances are very good I won’t ever run each of the circuits up to their rated capacity… but I’m the worrying kind…

My intention was to replace one of the existing 20a breakers with a 15a then add a second 15a breaker…. Which would give me 20a + 15a + 15a = 50a (plus the dedicated 50a RV outlet)

Yes? No? Other suggestions?

[Cummins12V98]

KnowNuthin wrote:

enblethen wrote:
Seems odd that using what I believe is a questionable solution :Drather than to install a 15- or 20-amp circuit and receptacle for the tractor.
Receptacle could be used for other purposes.

Next summer… I promise… I will install a dedicated 15a circuit for the tractor… but right now it’s too friggin’ cold…:D

I advise 12GA wire and 20A breaker.

[wa8yxm]

KnowNuthin wrote:

enblethen wrote:
Seems odd that using what I believe is a questionable solution :Drather than to install a 15- or 20-amp circuit and receptacle for the tractor.
Receptacle could be used for other purposes.

Next summer… I promise… I will install a dedicated 15a circuit for the tractor… but right now it’s too friggin’ cold…:D

GOOD ANSWER

[KnowNuthin]

enblethen wrote:
Seems odd that using what I believe is a questionable solution :Drather than to install a 15- or 20-amp circuit and receptacle for the tractor.
Receptacle could be used for other purposes.

Next summer… I promise… I will install a dedicated 15a circuit for the tractor… but right now it’s too friggin’ cold…:D

[enblethen]

Seems odd that using what I believe is a questionable solution rather than to install a 15- or 20-amp circuit and receptacle for the tractor.
Receptacle could be used for other purposes.

[Mike134]

KnowNuthin wrote:

Grit dog wrote:
Gittin a little deep and off topic for a simple plug in your block heater question that the conundrum has been solved already.

I belong to another, motorcycle related web board where I, along with seven others, perform the job of moderator…

I’ve come to the realization that, Eventually, “Off topic” is standard operating procedure in most threads… if the OP continually brings the focus back to center the thread will live on with much relevant information brought forth…

As moderator, I humorously pointed out to one of our newer members that the official record was five posts before the thread went completely off the rails… gave him the advice: “keep bringing things back to your original issue and ignore the ‘fluff’…”

I guess we should be thankful we got well into page 3 before things began to go sideways…

…and, yes, I’m thankful to all those more electrically knowledgeable than myself who kept me from frying my barn/tractor/electrical system…

You made it to 3 pages before going sideways because of less "experts" Now if you want to go sideways quickly ask how will my 1/2 ton handle a 8000lb 30 foot travel? (it does well don't listen to forum garbage)