Can you ground outlets by replacing them with GFCI?

Discussion in 'Electrical and Wiring' started by farmerjohn1324, Aug 5, 2018.

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  1. Aug 5, 2018 #1

    farmerjohn1324

    farmerjohn1324

    farmerjohn1324

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    I have a house built in the 1950s. None of the original outlets in the house are grounded. Can I ground them by replacing them with GFCI's?

    Maybe "ground" isn't the right word, but can I protect from power surges?

    https://www.thisoldhouse.com/ideas/replacing-two-prong-receptacles

    This site says yes, but I've heard conflicting stories.
     
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  2. Aug 5, 2018 #2

    hornetd

    hornetd

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    Let's separate the issues shall we. The National Electric Code allows you to replace an ungrounded two slot receptacle which is NEMA 1-15R type, with a NEMA 5-15R type three wire receptacle if that receptacle is protected by a Ground Fault Circuit Interrupter (GFCI). So for any given circuit there needs to be one GFCI which protects all the outlets which you are going to change to the 3 wire NEMA 5-15R type. That GFCI can be a combination GFCI Circuit Breaker, A stand alone GFCI that is mounted in it's own gang of an electrical device box, or a combination GFCI and NEMA 5-15R Receptacle that is placed between the receptacles to be replaced and the source of supply. All of the receptacles which are converted with a GFCI in place of an Effective Fault Current Path back to the source of supply must be Labeled "No Equipment Ground". This will provide a reasonable setting against electric shock if a portable appliance, such as a vacuum cleaner, develops a fault that energizes it's exterior conductive surfaces. As soon as the current begins to escape the circuit and flow through the human who is holding the vacuum cleaner the GFCI will open the circuit and shut off the flow of current in milliseconds. With the exception of Babies and those who already have an irregular heart rhythm this will prevent any injury but the shock will still hurt. The startle effect of the shock can cause you to fall because when you get shocked all of your muscles contract but the stronger ones win the internal tug-of-war. That is especially dangerous if you are on a ladder or right next to or on a stairway.

    Electrical surges are an entirely different matter. A surge is a destructive current flow caused by a sudden change in the supply voltage to the building. These voltage spikes are caused by a lot of different things which happen either inside or outside the building. A GFCI will not respond to a surge because the current flowing in the two wires is still the same. What is more likely to happen with a GFCI is that the surge will destroy it's sensing mechanism and it will fail safe with the circuit de-energized. A single surge can destroy a lot of electronic devices and a lot of appliance solid state controls. To protect your home and it's electrical appliances and devices from a surge you will have to install a whole house Surge Protector. A surge protector contains components which are connected between the separate wires of the circuit which will conduct if the voltage rises too high or too quickly. This equalizes the voltage between the wires of the circuit so that, even though the voltage may rise to several thousand volts for a few nano-seconds, no destructive current will flow because there is no substantial difference in voltage between the parts of the circuit. To actually protect all of your electronics you must protect all of the pathways which bring electrical current into your home. That includes coaxial cable and telephone wires. Since fiber optic cables do not carry electrical current you need not be concerned about them. This means that your whole house surge protector must include protection for all of the conductive pathways into your home.

    Still on surge protection you may want to add individual protectors to particularly expensive electronics such as televisions and computers. Once again the protector selected must include protection for all of the conductive pathways which connect to the device you are trying to protect. It is not uncommon for a television to have a coaxial cable, power cord, Ethernet cable, and even a phone cable. The protector chosen to protect it would have to include protection ports for all of these which are connected.

    --
    Tom
     
    Last edited: Aug 5, 2018
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  3. Aug 5, 2018 #3

    hornetd

    hornetd

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    I forgot to mention that you should check that there is no effective fault current pathway already in the circuit before you resort to GFCI protection. What makes a connection to an effective fault current pathway more effective is that the moment a fault occurs the leaking electrical current will be very likely to rise to a level that will cause the Over Current Protective Device, such as a fuse or circuit breaker, to open and that would be likely to occur prior to a person coming into contact with the energized surface of the faulty appliance. No shock means no startle effect and an even lower likelihood of injury.

    --
    Tom
     
  4. Aug 5, 2018 #4

    JoeD

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    To simply what was already said.
    You can replace two prong receptacles with three prong GFCI protected receptacles. All the receptacles do not need to be GFCI. One GFCI receptacle or a GFCI breaker can protect a bunch or regular receptacles.
    This does not create a ground it just allows three prong cord to be plugged in and be safe.
    It has nothing to do with surge protection. If the surge device needs a ground then this will not help you.
     
  5. Aug 6, 2018 #5

    hornetd

    hornetd

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    Any UL listed portable surge protector will still function on a 2 wire line that has no Grounding pathway. That is because the surge protector will equalize the voltage between all of the conductors which connect to the protected device even if one of those conductors is not connected to anything at the outlet. If the voltage remains the same between all of the conductive pathways to the protected appliance or other cord and plug connected load then there is no "Difference of Potential" to cause a destructive current to flow through the protected load . That is taken from a National Institute for Standards and Technology publication called Surges Happen. You will not find a more authoritative source on Surge Protection for the home. The presence or absence of a Effective Ground Fault Current pathway does not effect the function of listed Surge Protectors.

    --
    Tom Horne
     
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