Can Two Circuits Share A Ground Wire?


Safety should be the primary concern when working on the electrical circuits of your home. The first question that you should be asking is whether you should be modifying any of the electrics at all or whether you should get a professional in to do the work. If you are installing a new circuit in your home with the intention of getting it certified by an electrician before connection, then you may need to ask the question of whether two circuits can share the same ground wire.

So, can two circuits share a ground wire? While sharing a ground wire between circuits can work from an electrical point of view, it may not be allowed under the electrical code that governs your area. It is unwise to install electrical circuitry that does not comply with your local code. It is illegal and could be dangerous and cause you problems in the event of an insurance claim.

Electrical work in the home can be complicated, and your need to negotiate the minefield of staying within code for the standards that apply in your area. When it comes to electrical work, an electrical connection that may work from a technical point of view may not be legal from a code point of view. This is because the codes not only take into account what works but also what is safe from an electrical shock and fire prevention point of view.

What Does A Ground Wire Do In A Circuit?

The ground wire is a safety feature in electrical circuits. The earth has an electrical charge, which happens to be a negative electrical charge. This means that positive charges naturally want to flow to the earth to equalize the charge differential.

The ground wire is connected directly to the earth, literally embedded in the ground, and provides a safe, short, and direct path for a circuit overload to safely discharge. This will help to prevent electrocution or even the risk of fire when there is a fault or a short in the circuit.

The ground also protects the circuit from potential overload, for example, in a lightning strike. A lightning strike can create dangerously high voltages in your circuits, which could not only be dangerous for you but also burn out your appliances. The ground wire safely redirects this excess electricity to the earth. The earth literally disarms any extra, and potentially hazardous, electrical charge.

The ground is often referred to as the earth, and grounding is termed earthing because that cable or wire is connected directly to the earth, as in the planet. It’s interesting to note that grounding is the term most commonly used in the USA while earthing is more commonly used in the UK.

Ground Is Not Neutral

Inexperienced people often confuse ground with neutral. The neutral wire is part of the normal circuit, not a safety feature. The electricity goes to the appliance via the live wire and returns via the neutral wire.

The ground wire does not play a part until there is an overload situation. It would therefore be dangerous to confuse these two components of the circuit and connect them incorrectly.

Can Two Circuits Be Connected To The Same Ground?

There are various regulations that control this part of a circuit, especially when it comes to circuits within the home.

Incorrect installations can cause fires or serious injury, or even death if it is not done correctly. For this reason, the regulations have been put in place to ensure that electrical work is done according to certain standards to ensure safety.

The National Electrical Code or NEC sets standards for electrical circuits in the US and will determine the standards for grounding that you will need to comply with.

Some areas use the NEC 2011 code, while others use the NEC 2014 code, so you will need to find out which standard your area subscribes to. You would then need to consult the code to see what the rules are pertaining to grounding.

Essentially, within the NEC 2014 code, you can connect multiple circuits to the same ground as long as the circuits are all on the same bus and originate within the same circuit box or enclosure. This helps to not overload the grounding system and to protect electricians working on a circuit box that may be unaware of current coming from a different box.

If your area subscribes to the NEC 2011 code, for example, you are only allowed to add a grounding conductor either before or at the panel. The NEC 2011 code stipulates that each branch circuit must have an equipment ground. It is possible to share them when they are in the same raceway, and if the circuits are all of the same amperages, it can be one ground wire.

How To Find The Code For Your Area

Your local authority will be able to tell you which electrical standard that your area has adopted as a standard. A local electrician that works in your area will also be able to tell you which code is applicable in your area.

The electrical codes are modified from time to time, and sometimes areas adopt completely new code standards.

It is important that the correct code standard is followed since it will affect whether the wiring in your house is up to code or not. Wiring that is not up to code can have implications for any insurance claims should there be electrical or fire damage to your home.

Can You Simply Add A Grounding Electrode?

No, this is not a good idea since the earth is not a good conductor; the circuit needs to provide a low resistance path for the excess electricity to take the path to the earth so that the circuit breaker will be tripped.

Multiple grounding conductors need to be bonded together correctly in order to get the desired effect when a ground fault occurs in the system. Incorrectly installed grounding electrodes may not result in the circuit breaker tripping because of the relatively high resistance of the earth.

All additional grounding electrodes in the circuit would need to be bonded back to the main grounding conductor at the entry point of the mains supply or service equipment to the home.

Can Circuits Have More Than One Ground?

The situation where more than one ground is connected to a circuit is not normal practice in the electrical wiring of a home.

Generally, the only time where there s more than one ground is where there is a mixed analog and digital circuit, each of which may require its own separate grounding to minimize electrical noise in the system.

Therefore, no circuit in your home should have multiple ground connections, and you should not consider this as an option.

Consult An Electrician

An article such as this cannot cover all eventualities and codes that apply in all countries and all local municipalities.

For this reason, as well as for the safety of you, your family, and your home, it is best to consult with a local electrician before installing new circuits to your home or making modifications to existing circuits.

Where electricity is concerned, a little bit of knowledge can be deadly, and it is not worth taking the risk simply to save a little money.

Conclusion

Electrical wiring in your home should never be considered a DIY job that you can cobble together with a basic knowledge of high school level circuits. Wiring in the residential home needs to comply with standards for health and safety reasons.

Wiring a circuit in the home and having the attitude that if you connect it up and it works that everything is ok is a cavalier and unsafe mindset.

Our recommendation would be to consult an electrician in all electrical matters in your home. Some electricians may be willing for you to perform wiring yourself and have them check the wiring and connectors before it is connected to the main electrical supply. Others, on the other hand, would not be willing to do this since it takes a labor charge from their billing, and they may feel they cannot certify an installation that they did not conduct themselves.

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