Electrical – Is it possible to self install a grounding rod


This has been a baffling question as I notice electrician charge an arm and a leg to upgrade electrical systems in a home. My home was built in the 1930s and it’s not grounded. I was wondering if a grounding rod is just a long stick that goes deep down in the ground. If so, how deep should I drill? Second, if I just connect that to the cold water pipe, I can ground all my outlets to that cold water pipe?

Best Answer

Absolutely not

You may not use water pipe in your home as a substitute for ground wiring between outlets and panel. That won't work, isn't legal and will create the illusion of safety - a lot like taking your shoes off at the airport.

However in 2014 the rules for properly retrofitting grounds were greatly relaxed. It's no longer necessary to replace the entire cable, now you can simply fit a bare or green wire between the outlet and the service panel which serves it.

There's a lot more to a grounding system than that

Electricity travels in loops. It wants to return to the generation source, not ground. Ground isn't a very good conductor anyway. There are two general groups of threat:

  • natural electricity that actually does want to return to ground, because that is its source -- lightning and ESD.
  • man-made electricity which is not where it should be. We want it to find an alternate path back to source that is much better than shocking a human.

Grounding systems are confusing because they are trying to solve two very different problems at once. As such, they do two very different things at once. Do not confuse them. Do not think one is a substitute for the other.

The heart of it is the service panel

Inside your service panel, you have two buses: neutral and ground. Neutral is the normal current return back to source. Ground is the equipment safety grounding system, designed to catch abnormal current flow. Neutral and ground are kept rigidly separated.

Neutral is bonded to ground at exactly one location: the main service panel, and this is called the neutral-ground bond. This can look pretty casual: sometimes you see bars with all the neutrals and grounds spammed onto the same bar, that had better be the main panel. In a subpanel they are rigidly separated.

What does this neutral-ground bond do? First it assures that abnormal current caught by the grounding system is able to return to source. Second, it makes sure all the conductors remain at sane voltages compared with your grounding system (e.g. in case the power company's transformer has a problem).

The grounding electrode system

This system provides a connection to actual physical earth. Yes, it can involve a water pipe. Code specifies what is acceptable. Do one of those.

It's then tied to the ground bar in the main service panel. Other grounding electrodes may be required, i.e. At outbuildings, and those are also tied to the grounding system.

What does the grounding electrode system do? First, it provides a route for natural electricity to return to its source - earth. Second, it gives the ground bond a way to pull neutral down to actual earth voltage (or to be more precise, pull the earth around your house up to leaky-transformer voltage, which is the least ugly way of handling that problem.)

From the ground bar, runs to every outlet

And don't do a homerun for each outlet. When you are retrofitting grounds, circuits out of the same panel can share the ground wire, as long as it's big enough. So you don't need to reach the panel, any other grounded point will do if it's big enough. So you can do a "tree" layout for all your grounds. You can share grounds when retrofitting, you cannot share neutrals.

Ground wires do not need to follow the route of the live wires. They can use any practical route.

Start by planning a ground wire to hit your biggest loads, which will be #10 or so. Then provide junction boxes in the right places so your smaller ground wires can start at one of those, and then daisy chain to all your outlets.

To get ground wire, you can shuck down old Romex that is damaged or otherwise unusable. You need to strip it down to bare wire (so ratty or damaged insulation won't be a factor). Don't use nicked or damaged parts, obviously. Copper is a pure metal that inherently resists corrosion and doesn't go bad.