Dear Mr. Electrician: How do I fix my in-ground swimming pool bonding?
Answer: Swimming pool bonding can be easy to fix if you know the National Electrical Code requirements. Article 680.26 Equipotential Bonding is what is used to determine the swimming pool bonding requirements. NOTE: Some text links below go to applicable products on Amazon.
Below are photos of a commercial pool that failed inspection due to shortcomings with the pool bonding.
In my state commercial swimming pools are required to be inspected by a licensed electrical contractor every few years. The required inspection is a good thing, because every time I have done a pool inspection I have found problems. Most problems were not from the original swimming pool construction, but as a result of repairs, changes, and a lack of good preventative maintenance.
Unfortunately the state has no such inspection requirements for homeowner managed swimming pools. Consequently problems on homeowner swimming pools such as a lack of bonding are not caught unless someone working on the pool notices that something is wrong.
SWIMMING POOL BONDING REPAIR
This is a close up shot of the pool pump from the top of this page. Although it does have a bonding wire connected, the lug is not approved for two wires, only one. The photo below depicts my correction.
A new tin plated copper lay-in lug was installed and the broken bonding wire was spliced together using a copper C tap and a crimping tool. I also used copper split bolt connectors to take the strain off of the crimps.
The swimming pool pump motor above has its own built-in lay-in lug and set screw.
Lay-in lugs are favorable for use on swimming pool equipment because it makes it easy to replace pool equipment without having to take apart all of the bonding connections.
A swimming pool heater with a lay-in bonding lug and number 8 solid copper bonding wire.
The above swimming pool lighting transformers were all required to be bonded. One of the bonding lugs had two wires in it. That would have been okay if the lug was approved for two wires, but it wasn’t.
Two wires in a pool equipment bonding lug that was not approved for two wires. My fix is below.
I pulled the extra wire out of the lug and made a splice using a copper crimp and a copper split bolt connector.
I used a copper C tap crimp and also a copper split bolt connector to join the wires together for a low resistance connection.
The original installer installed a bonding lug on the top of the outdoor wiring trough. It would have been better if the lug was on the bottom to keep water out, but there was probably no room to get an electric drill underneath after the lighting transformers were installed.
It is acceptable to use only copper split bolt connectors for the #8 solid copper pool bonding wire. Crimped connections are not required for pool bonding.
The brackets that support the pool controls were just fastened to the concrete slab with some L brackets. Consequently the pool controls were a little shaky and the upright strut supports could be easily swayed.
Due to the close proximity of the service door for the pool heater I could not install some larger brackets for support. I basically rigged some Unistrut and strut fittings onto the existing concrete bolts and strut and that made the pool controls more secure.
I drilled and tapped holes in the strut and used stainless steel 10/32 screws with nuts to attach the lay-in lugs.
I spliced some #8 copper wire onto the existing #8 bonding wire to extend the bond to the pool control support posts. Insulated wire or bare wire is acceptable for pool bonding, but it must be #8 solid copper wire. Do not use stranded wire for pool or hot tub bonding.
OTHER SWIMMING POOL BONDING REQUIREMENTS
In addition to what is shown above, the pool bonding wire must also be connected to the pool deck perimeter usually by connecting to the wire mesh or rebar in the concrete. A bond wire is required in the pool deck perimeter even if there is no concrete.
All metal handrails, ladders, water spouts, diving boards, water slides, pool lighting, and the pool shell must also be connected to the solid copper #8 continuous swimming pool bonding wire. Anything metal within three feet from the inside wall of the pool must also be bonded to the same #8 wire.
Article 680 in the National Electrical Code (NFPA 70) has all of the grounding and bonding requirements for all types of in-ground and above-ground swimming pools, hot tubs, fountains, and similar types of artificial bodies of water.
For other grounding and bonding topics written by me click here.