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?

[Grit_dog]

toedtoes wrote:


That works. If this is going to be a yearly need, you could size the cut to exactly the length needed. I'd say take a 50ft cord and make two 15 feet and a 20 foot from it - that gives you a couple shorter cords for when you are RVing.

Or NOT do what some people think is a good idea (hacking a perfectly good expensive waterproof cord into multiple chunks) and just put it in a bucket or cover the cord from UV if it's sitting outside all year.

Especially since it was established in the first post that there is no need for any sort of "HD" power cord anyway (to run the block heater on the tractor).

[toedtoes]

KnowNuthin wrote:
My tractor is parked next to the wall where the electric service is located… less than 10’…. My shortest HD extension cord is 50’…

Part of the reasoning behind my original idea was so II could plug a custom length cord directly into the outlet…

I might just cut one of my cords in half and get two replacement ends to create shorter cords… the 50’ one I’m using for my diesel pickup block heater gets warm when used…

That works. If this is going to be a yearly need, you could size the cut to exactly the length needed. I'd say take a 50ft cord and make two 15 feet and a 20 foot from it - that gives you a couple shorter cords for when you are RVing.

[KnowNuthin]

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…

[Grit_dog]

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

[wa8yxm]

Bobbo wrote:

ktmrfs wrote:
the lamps are likely using a 14 or 16 ga wire, entirely capable of handling 15 or 20A for a short period of time if the lamp were to cause a short. A 12Ga extension cord is NOT capable of handling 50A for any length of time.

Nope. It is 18g.

Even 18 ga in air (not buried in a wall) can handle 20 amps plus long enough to trip a breaker or blow a fuse.

You need to understand the difference between air and insulation.,

[Bobbo]

ktmrfs wrote:
the lamps are likely using a 14 or 16 ga wire, entirely capable of handling 15 or 20A for a short period of time if the lamp were to cause a short. A 12Ga extension cord is NOT capable of handling 50A for any length of time.

Nope. It is 18g.

[rhagfo]

enblethen wrote:
Your 50 amp should be a double pole breaker.
I think it is a bad idea for what you are thinking.
I would suggest getting thin breaker with two 20-amp breakers and installing a new receptacle. Some call breakers, wafer or tandem.

X2!
Best, safest way to go!

[wa8yxm]

LittleBill wrote:
so do all you guys who have 15 amp circuits in your house, where your lamps are plugged in use a 1 amp circuit breaker to each individual lamp?

Most all the lamps I've seen are wired with 15 amp wire and thus need nothing smaller.

Some lamps (Like Christmas tree lamps) have smaller wire.
And generally fuses in the plug body.

18 ga (Lamp cord) in open air has no problem with 15 amps for short runs.

[KnowNuthin]

My tractor is parked next to the wall where the electric service is located… less than 10’…. My shortest HD extension cord is 50’…

Part of the reasoning behind my original idea was so II could plug a custom length cord directly into the outlet…

I might just cut one of my cords in half and get two replacement ends to create shorter cords… the 50’ one I’m using for my diesel pickup block heater gets warm when used…

[toedtoes]

If you are using anextension cord, you might use your 50amp extension cord from the outlet, then put the pigtail(s) at the end of the cord. That way you'll have a 50amp gauge cord for most of the length.

[Grit_dog]

KnowNuthin wrote:

Grit dog wrote:


There are a few options, not entirely clear without seeing your sub panel, but seems the easiest and safest no brainer is get a 30-20A pigtail and not ever touch the hot side of the box.

This is the Load center I have…

There are a couple vacant slots still available for future circuits… however… it’s currently 16 degrees outside with snow forecast for the next few days…

I’m trying to make this a plug-and-play scenario for now… a plug in 50a adapter and an extension cord makes my time away from a cozy fire much less…

Lol, I'd do the same if it's already winter!
Wow, 16 deg on the Front Range already?
But you're right, looks like it would be no problem to add another circuit in the future real easy for some more convenience power.

[KnowNuthin]

Grit dog wrote:


There are a few options, not entirely clear without seeing your sub panel, but seems the easiest and safest no brainer is get a 30-20A pigtail and not ever touch the hot side of the box.

This is the Load center I have…

There are a couple vacant slots still available for future circuits… however… it’s currently 16 degrees outside with snow forecast for the next few days…

I’m trying to make this a plug-and-play scenario for now… a plug in 50a adapter and an extension cord makes my time away from a cozy fire much less…

[ktmrfs]

Bobbo wrote:

LittleBill wrote:
so do all you guys who have 15 amp circuits in your house, where your lamps are plugged in use a 1 amp circuit breaker to each individual lamp?

I was going to type this very thing on reaching the end of the thread. You beat me to it. Every one of my 1/2 amp (60 watt) lamps is plugged into a 15 amp outlet protected by a 20 amp breaker. Yes, I am risking the 18g wire shorting out and melting creating a fire hazard. I don't care.

the lamps are likely using a 14 or 16 ga wire, entirely capable of handling 15 or 20A for a short period of time if the lamp were to cause a short. A 12Ga extension cord is NOT capable of handling 50A for any length of time.

[ktmrfs]

enblethen wrote:
The lite wire becomes a fuse if you use the 50 ampere's circuit. Failure in the heater could cause wire to melt down and create a fire situation.

EXACTLY!!! whole point is to make sure the wiring downstream of the breaker can handle the max breaker current in the case of a downstream fault. !!!!!

[Bobbo]

LittleBill wrote:
so do all you guys who have 15 amp circuits in your house, where your lamps are plugged in use a 1 amp circuit breaker to each individual lamp?

I was going to type this very thing on reaching the end of the thread. You beat me to it. Every one of my 1/2 amp (60 watt) lamps is plugged into a 15 amp outlet protected by a 20 amp breaker. Yes, I am risking the 18g wire shorting out and melting creating a fire hazard. I don't care.