Sahib's Concern Over 240V to a Duplex

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T.M.Haja Sahib

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As far as I know duplex receptacles are rated for 125V, then how about when electricians use one duplex for dish washer and disposal, and break off the bridge to separate hot portion of each receptacle, then feed it with 12/3 (2 circuits on A, B phases). Now duplex is receiving 240v.
Go ahead please and post yoour thoughts. Thanks.

Your apprehension is justified.A housewife can be subject to a 240V shock if she is handling two appliances such as dish washer and disposal at the same time in the kitchen and which are connected to that one duplex receptacle.But what to do when the code panel ruled it is safe!
 

Dennis Alwon

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Your apprehension is justified.A housewife can be subject to a 240V shock if she is handling two appliances such as dish washer and disposal at the same time in the kitchen and which are connected to that one duplex receptacle.But what to do when the code panel ruled it is safe!

That has nothing to do with it Haja. That ruling has to do with overloading the outlet and also protecting the worker. A mwbc on two single receptacles would also need handle ties for the workers protection.

From what you stated the homeowner is subject to a 240V shock if two appliance are on opposite phases. Not likely esp. if the system is grounded properly. If that were the case we couldn't have 2 phases in the same kitchen.

BTW, I do the kitchen work as much as my wife does.....
 
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T.M.Haja Sahib

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From what you stated the homeowner is subject to a 240V shock if two appliance are on opposite phases. Not likely esp. if the system is grounded properly.

Think again.

Grounding has nothing to do with avoiding that 240V shock:just imagine current flow from one line conductor to another conductor through one hand to another hand of that unfortunate housewife.
 

Dennis Alwon

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Grounding has everything to do with it. If the appliance is grounded and the frame comes in contact with 120V the circuit will trip. The chances of 2 bad grounds and the appliances being shorted at the same time would be very slim. Think about what you are asking for-- a kitchen wired all on the same phase. You still can get killed with 120V so the argument is not meaningful.
 
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T.M.Haja Sahib

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Grounding has everything to do with it. If the appliance is grounded and the frame comes in contact with 120V the circuit will trip. The chances of 2 bad grounds and the appliances being shorted at the same time would be very slim. Think about what you are asking for-- a kitchen wired all on the same phase. You still can get killed with 120V so the argument is not meaningful.

Which has greater likelihood of causing injury 120V or 240 V ?

Why this nation adopted 120v instead of 240V?
 

Dennis Alwon

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Which has greater likelihood of causing injury 120V or 240 V ?

Why this nation adopted 120v instead of 240V?
That is irrelevant. If you want to use that argument then I will tell you it is a known fact that there are more injuries due to 120V then to 240V. That means nothing.
 
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T.M.Haja Sahib

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If you want to use that argument then I will tell you it is a known fact that there are more injuries due to 120V then to 240V. That means nothing.

No.It is simply because the country adopted mainly 120 V supply.
 

raider1

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Your apprehension is justified.A housewife can be subject to a 240V shock if she is handling two appliances such as dish washer and disposal at the same time in the kitchen and which are connected to that one duplex receptacle.But what to do when the code panel ruled it is safe!

Then the house wife should not be doing any laundry or cooking on the stove because she will be subjected to a potential 240 volt shock as well.:rolleyes:

Chris
 

charlie b

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A housewife can be subject to a 240V shock if she is handling two appliances such as dish washer and disposal at the same time in the kitchen and which are connected to that one duplex receptacle.
Only if both appliances simultaneously experience an internal fault that causes their respective external metal parts to become energized. This is an extraordinarily unlikely event. But if it did happen, the equipment grounding conductor will do its job of carrying a high enough fault current back to the source so as to cause the breaker to trip. The code book authors correctly concluded that this is not a safety concern.
 
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charlie b

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Think again. Grounding has nothing to do with avoiding that 240V shock:just imagine current flow from one line conductor to another conductor through one hand to another hand of that unfortunate housewife.
Current will not flow from either line conductor into a person's hand, unless that line conductor comes into contact with the external metal parts of the appliance. That would bring about the circumstances I mentioned just above, and the grounding has everything to do with it. It is your turn to think again.
 

iwire

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Current will not flow from either line conductor into a person's hand, unless that line conductor comes into contact with the external metal parts of the appliance. That would bring about the circumstances I mentioned just above, and the grounding has everything to do with it. It is your turn to think again.


Charlie, I think you have overlooked the possibility of the house wife disassembling both appliances while live and holding the ungrounded conductor from each in their hands.
 

charlie b

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Which has greater likelihood of causing injury 120V or 240 V ?
This was the subject of a fairly long debate on this forum, and not that long ago. Look it up, if you wish to see who believes what. I will only state my answer: Neither 120V nor 240V has a greater likelihood of causing injury than the other, for the simple reason that "being dead is the same as being dead."
 
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T.M.Haja Sahib

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Then the house wife should not be doing any laundry or cooking on the stove because she will be subjected to a potential 240 volt shock as well.:rolleyes:

Chris
Is there any meaning in 'minimizing electrical shock risk'or not?
 

charlie b

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Charlie, I think you have overlooked the possibility of the house wife disassembling both appliances while live and holding the ungrounded conductor from each in their hands.
You are quite right, of course. Mea culpa, mea culpa, mea maxima culpa. :ashamed1:
 

charlie b

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Is there any meaning in 'minimizing electrical shock risk'or not?
Yes. One accomplishes this goal by not tearing apart electrical appliances while they are plugged in. It should be noted, however, that the act of doing laundry (and I do my share of this chore at home) does not involve tearing the washing machine apart. I think the same can be said for the act of cooking.
 
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T.M.Haja Sahib

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I think you have overlooked the possibility of the house wife disassembling both appliances while live and holding the ungrounded conductor from each in their hands.

Oh,My God.You are back.I must make quick exit.:D
 

Hv&Lv

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In reading this thread, I am reminded of the receptacles in my bathroom. I have a 20 amp duplex receptacle, with the hot tab removed. 120V on one receptacle, and the opposing 120V on the other receptacle. This way my wife can plug in her hairdryer(1800W) and curling iron(1500W) in the same duplex and not trip the two pole 20 amp breaker. I agree that when split, the receptacle becomes two individual receptacles. According to Haja, wouldn't she (shouldn't she) have been shocked and killed by now?
 
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