Dear Mr. Electrician: How do I fix my in-ground swimming pool bonding?
Answer: Although swimming pool bonding is not very difficult to fix if you know the National Electrical Code requirements, it is best left to professionals due to the high risk of injury or death if done improperly.
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Article 680.26 Equipotential Bonding is what is used to determine the necessary swimming pool bonding methods needed for each pool.
Bonding of swimming pools, hot tubs, and other immersion pools is extremely important to reduce electrical shock hazards and the possibility of electrocution.
Water and electricity are not a very safe combination so it is imperative that the electrical installation be done according to the National Electrical Code and local code requirements.
Below are photos of a commercial pool that failed inspection due to shortcomings with the 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 residential homeowner pools are not caught unless someone working on the pool notices that something is wrong.
BONDING WIRE 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 with a new lay-in lug and crimped wires.
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 a copper split bolt connector 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 pool equipment because it makes it easy to replace the equipment without having to take apart all of the bonding connections. The bonding wire should never be cut.
A pool heater with a lay-in lug and number 8 solid copper wire. All equipment associated with a pool must be bonded.
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 wire. Crimped connections are not required for pool bonding.
The strut risers that support the pool controls were only fastened to the concrete slab with some L brackets. Consequently the pool controls were a little shaky and the upright strut could be easily swayed.
Due to the close proximity of the service door on 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 to the strut.
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 POOL BONDING REQUIREMENTS
In addition to what is shown above, the pool bond wire must also be connected to the pool deck perimeter usually by connecting to the wire mesh or rebar in the concrete using rebar ground clamps. 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, underwater audio equipment, pool cover motor, and the pool shell with rebar must also be connected to the solid copper #8 continuous swimming pool bond wire. Anything metal within three feet from the inside wall of the pool must be bonded to the same #8 wire.
In addition, according to article 680.26(C) the water of the pool must also be bonded. This is accomplished by installing one or more special water bonding fittings designed for that purpose. The fittings can go on the pool pump water pipes or in the skimmer or by other means.
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.
Visit this website article for a lot more details about swimming pool bonding.
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