Electric question

Was at a friends house today in his shop ie man cave what ever.
Long story shortened.

Since the walls do not have sheetrock I noticed a 110 plug.
It has a wire running from a 110 plug to this 110 plug to a 220 plug.
I asked what is this.
He said the 110 window A/C unit kept tripping the breaker so another friend installed a different plug for him.

So I looked it over.
He has a 14 gauge wire running to the shed for a 110 plug and a couple of pull string lights.
It has a hot neutral and ground.
He has a 10 gauge wire running to a 220 plug I think he uses for a air compressor.
It has 2 hots and a ground.
Both these wires run back to a mobile home electric pole with proper breakers.
So far so good.

Now it gets interesting.
The 110 A/C was tripping the 15 amp breaker with the 14 gauge wire.
So they installed a new 110 plug.
They ran a 12 gauge wire from this plug and tapped into one leg of the 220 plug.
They then ran a 12 gauge wire and tapped it into the 14 gauge neutral wire.
I do have to applaud them though as they did use a neutral wire rather than a ground wire.

So tell me the good bad and ugly of this setup.
Way I see it the breaker on the 220 wire may have a hard time tripping if this A/C unit has a problem.
But mostly I would be afraid of using a 14 gauge neutral wire on a A/C that most likely needs 12 gauge wire and a 20 amp breaker.
 
The 20A breaker will still trip if overloaded only on the one leg. The 14 ga wire might be getting a little warm at that point though. Also likely has excessive voltage drop. Now if the 110 outlet happens to be fed by the opposite hot from the A/C unit. Placing a load on the 110 outlet would drop the current in the 14 ga wire.

In my shop panel, I have a 30A double breaker ganged with a 20A single. If the 20A trips it takes the 30A with it. It is done this way since both feed outlets in the same box. That way the power is killed to both circuits if you open the outlet box, and not just one side.
 
Bad news: Appears to have several code violations. Good news: It appears to work and if the 14ga wire has a meltdown, there is no drywall to conceal it.
 
If they overloaded the 110v line on the 14 gauge wire the wire would probably come to the melting point before it would trip the 220v breaker. They are just lucky they got the right leg on the 220 to tie into. If they tied into the other one it would be the fourth of july.
 
Good news is he can see the smoke.
Bad news is he's running an ac without a ground wire. Worse news is he's using 14g wire. Even worse is letting Bubba help him with electrical wiring after consuming a few.
The ugly is the whole thing!
 
John
Your post is too long and confusing for me.
I need another cup of coffee.
Pictures would help this old man.

What many don't understand is anything with a motor needs
5 to 10 times the amps to start it.
AC should operate on a single circuit. Single circuit; one breaker, one outlet.

I need coffee.
 
20 amp feed and 15 amp return,,, with a 20 amp breaker on the feed side.... The return is now a heater wire like a toaster. What could possible go wrong.
 
(quoted from post at 05:05:35 03/27/23) If they overloaded the 110v line on the 14 gauge wire the wire would probably come to the melting point before it would trip the 220v breaker. They are just lucky they got the right leg on the 220 to tie into. If they tied into the other one it would be the fourth of july.

No. It would not matter which hot leg of the 220 he tied into. He'd get 110. Neutral is neutral, all on the same bus bar in the panel.

I assume this is an old school 220 circuit, hot hot ground.

All he would really have to do is run a 10ga neutral to the pole for the AC outlet.

IDEALLY he would run a third dedicated circuit for the AC.

Alternatively he could wire the 220 circuit to a subpanel and branch 220 and 110 circuits off that, BUT he'd still need to run a neutral.
 
Good question John, hey you have been around and have a good handle on this electrical stuff Im sure, but for the others benefit I will address your question: So tell me the good bad and ugly of this setup.

Here's the deal: Unfortunately, I don't see much good but mostly BAD including potential NEC violations. As usual any legal or electrical questions draw out the most and varied responses so I will try to clear up any possible confusion.

1) As far as being hard or easy to trip a 220 breaker FYI it does NOT matter that it happens to be a One or a Two Pole BREAKER, HOWEVER, what determines how hard or easy it is to trip DEPENDS ON ITS CURRENT RATING. Is it a 15 or a 20 or a 30 amp ??????? Thats what determines when it trips, NOT because its a one or two pole !! In the event it uses 10 Gauge wire, thats a hint it may be a 30 Amp which indeed takes more current to trip versus if it were a 15 or 20 ....... BUT YOU CANT USE 12 OR 14 GAUGE WIRE FED FROM A 30 AMP BREAKER, regardless if its a Single Pole 120 or Two Pole 240 !!!!!!!!

2) Safety, the NEC and basic electrical theory 101 tells us that the overcurrent protection device (fuse or breaker) is selected to protect the wire sooooooooooo if 14 gauge 15 amp rated wire is in the circuit YOU CANT USE MORE THAN A 15 AMP BREAKER IE if the breaker is 20 amp (one or two pole), you can NOT use 14 gauge 15 amp rated wire YOU NEED 12 GAUGE 20 AMP RATED WIRE !!!!!!!!!!!!! O

3) Its typical for a pure 240 volt (NO 120) load to use two hots L1 and L2 PLUS an Equipment GroundiNG Conductor NO NEUTRAL REQUIRED. The wire and breaker size is determined by the loads Maximum Continuous Current and may result in a 15 or 20 or 30 or more circuit.

4) Its generally NOT permissible (there are a few very limited Tap Rule exception under the NEC) to tap off of a 30 amp protected circuit or receptacle etc AND THEN RUN 12 OR 14 GAUGE WIRE over to another load or receptacle etc. HAZARDOUS AND NEC VIOLATION for 12 or 14 or smaller wire to be on a circuit with a 30 amp breaker !!!!!!!!!! Well DUH even Bily Bob and Bubba surely know that lol

There are several ways to do this safe correct and in compliance with the NEC that are NOT rocket science as long as the basics above are followed, please advise the gentleman accordingly, the fire or life he saves may be his own !!!!!!

John T Nooooo Warranty (Im too long retired as an EE), where fire and life safety are concerned at least consider consulting with a trained professional electrician or engineer versus mine or anyone elses advice.
 
It takes around 200 amperes to melt 14ga wire, so don't get too alarmed over an extra 5 amperes. May not be "code", but not a 5 bell alarm either,
 
Mornin my sparky friend JMOR, Good point concerning how much current it takes to melt a certain size wire,
however, as I'm sure you're well aware (BUT FOR THE BENEFIT OF OTHERS) the rating of a particular size
conductor covered with a certain type/class of insulation has most to do with how much current it can safely
carry WITHOUT DEGRADING THE INSULATION, NOT so much the HUGE amount of current it takes to melt the wire
yikes !!! AND AS YOU WELL KNOW AND POINTED OUT THATS ONE HUGE DIFFERENCE !!!!!!!!

John T It was my business, profession and duty to be concerned with, worry and design in accordance with
accepted standards BUT LIKE YOU I AGREE A FEW AMPS OVER MAY NOT RAISE A 5 BELL ALARM FOR AVERAGE USERS
 
(quoted from post at 12:04:07 03/27/23) Mornin my sparky friend JMOR, Good point concerning how much current it takes to melt a certain size wire,
however, as I'm sure you're well aware (BUT FOR THE BENEFIT OF OTHERS) the rating of a particular size
conductor covered with a certain type/class of insulation has most to do with how much current it can safely
carry WITHOUT DEGRADING THE INSULATION, NOT so much the HUGE amount of current it takes to melt the wire
yikes !!! AND AS YOU WELL KNOW AND POINTED OUT THATS ONE HUGE DIFFERENCE !!!!!!!!

John T It was my business, profession and duty to be concerned with, worry and design in accordance with
accepted standards BUT LIKE YOU I AGREE A FEW AMPS OVER MAY NOT RAISE A 5 BELL ALARM FOR AVERAGE USERS
s you said, yes I am aware. Just a shot across the bow of worry warts. :) In aircraft design, where every pound counts, the insulation quality/types allow engineers to run more current & higher CB ratings than in typical residential wiring of same gauge. Insulation is the big factor.
 
To be clear, the oft quoted 15A 14ga, 20A 12ga from the NEC are for residential structure in-wall wiring. There are a number of other amperage tables in the NEC code for conductors in other situations that allow for higher amperages based on the insulation type, enclosed vs. free air, etc.
 
EXACTLY, back when I studied and practiced pursuant to the NEC, the ampacity varied based on the enclosure,
if in conduit what size conduit and how many enclosed conductors, if jacketed the material and type of
conductors, the type and class of insulation and temperature, and as you indicated a single conductor in
free air has a much higher rating !!!!!!!!!

Yayyyyyy for the NEC lol

John T
 
Insulation is the big factor

DITTO and X2 I typically specified THHN or THWN for single conductors enclosed in conduit..

John T
 
It does seem it would have been easier to do it correctly. Simple solution get a 220-air conditioner.
 

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