What are the electrical concerns with SWG?

[Denis54]

I have a 220 V 30 A "ground protected" electricity supply to my pool equipment and I want to add a SWG. My local pool shop says I need a special electricity supply for a SWG and that I can expect a $400 (cdn) bill.

Are there any specific electricity dangers associated with SWG?

Among others he said my pool stair need to be grounded. Any truth to this?


P.S. I am french canadian and english is a second language to me. Please forgive me if my technical description is not clear.

[PatL34]

Denis,

Welcome to the Forum.

There is no need to have a special electricity supply. You should be able to connect the SWCG off the timer. Many have installed SWCGs themselves, without any problems.

Regarding the pool stairs, you may need to connect a ground wire back to ground connection on your "ground protected" supply. It's called a GFCI (ground fault current interrupter) in the US.

If the electrical codes allow you to instal it then go ahead. I did mine myself.

Pat

[JohnT]

If your pool stairs are metal, they need to be bonded. Has nothing to do with grounding. Bonding is simply connecting everything conductive involved with the pool together with a wire. It is for safety, and has nothing to do with the pool's electrical system.

[tenax]

i question the bonding process as i read time and time again in manuals it appears to be an issue if your electrical equipment is within x feet of pool. for example, i too have a set of metal stairs..aside from that and various screws, no metal in the pool..the pool is about 40 ft away from my pool shed so how the heck would a person bond the stairs..and do you need to at that distance? (ps- i note none of my electrical stuff has a bonding wire..pump, heater..when i put my swg in, i'll bond all those items)

thanks

[JohnT]

i question the bonding process as i read time and time again in manuals it appears to be an issue if your electrical equipment is within x feet of pool. for example, i too have a set of metal stairs..aside from that and various screws, no metal in the pool..the pool is about 40 ft away from my pool shed so how the heck would a person bond the stairs..and do you need to at that distance? (ps- i note none of my electrical stuff has a bonding wire..pump, heater..when i put my swg in, i'll bond all those items)

thanks

You run the wire underground to the shed. It's usually put in the plumbing trench.

[Denis54]

What is the pupose of "bonding"?

What are the dangers associated with an "unbounded" pool?

My pool shed is located 30 feet from my pool. Does that decrease potential danger?

Does SWG increase any potential dangers associated with an "unbounded" pool?

My pool whas constructed 20 years ago. I really do not remember if all conductive materials were connected with a wire but I never had any problem in the past.

[tenax]

Denis, just doing some reading up on this, it appears the us electrical code insists you bond everything metal regardless of distance. in canada, the coding is somewhat difference. my pool stairs, light are bonded..nothing in my shed is. if the equipment were within 5 ft of the pool, it would have to be as well. but my shed is 30 ft plus away from the pool..which explains why nothing in my shed was which at first surprised me before i started reading up on this. in the canadian code, the rationale given is that i actually want the pool electrical items ISOLATED from the metal items at the pool rather than bonded to..which seems somewhat logical to me.oh well:). in regards to ponding metal items around the pool, my understanding is that you can get a variety of shocks from minor to major..you want to get any potential electrical shocks to ground quickly. the #8 copper wire does that so the electricity doesn't travel to your body..i don't quite understand the difference between "grounding" and "bonding" but..can see the concern. read a story recently about a woman who had a pool and in certain areas of it, they would get a very mild shock. they believe it's due somehow to some power poles added behind their place recently and apparently other people with pools by them are getting some mild shocks as well.

[JohnT]

What is the pupose of "bonding"?

What are the dangers associated with an "unbounded" pool?

My pool shed is located 30 feet from my pool. Does that decrease potential danger?

Does SWG increase any potential dangers associated with an "unbounded" pool?

My pool whas constructed 20 years ago. I really do not remember if all conductive materials were connected with a wire but I never had any problem in the past.
Bonding makes sure that all conductive materials that a swimmer might contact are at the same voltage. With electricity, it's not the voltage that hurts you, it is touching two points that are at different voltages which causes current to flow through your body.

An example of what bonding can protect from:

You place an AC powered radio on the concrete deck of the unbonded pool. Splashing around causes the deck and radio to become wet. Now the deck is at 115VAC. A swimmer starts to climb out of the pool with a hand on the metal ladder. They are electrocuted when they contact both the wet deck and the ladder at the same time. If the pool had been properly bonded, the rebar in the deck and the ladder would have been wired together, so the ladder and the deck (and even the water in the pool) would have both been at 115VAC, so no electrocution.

Bonding probably most often benefits by preventing stray voltage related minor shocks when touching the deck or ladder.

The big issue with bonding the pool equipment is that the pool itself will often/usually/sometimes/who knows be grounded by it's own contact with the earth, but often the water will be at an unknown voltage because it isn't in contact with anything conductive. If a fault occurs at the pump or heater etc., the water can become energized at a different voltage than the deck.

All of these scenarios are pretty rare, and other safety equipment like GFCIs and common sense should be the first line of defense, but there are real world examples of people being killed by rare events in pools with unbonded equipment. One that impressed me was a lifeguard in contact with an improperly replaced lifeguard stand who was electrocuted when a trackhoe working nearby contacted a power line with its boom. No way could the pool operator have controlled what happened, and the voltage of the earth was raised to several thousand volts in the area.

I would say that the long distance to the pool shed actually increases the danger, in that the earth in the area of the pool is more likely to be at a different voltage than that at the service entrance.