Electrical Pool Lights wiring question...

[PoolWayne]

Thanks in advance for input. My experience level is very high (mechanical engineer), but not to the level of a professional. I've done light switch replacements and simple fixes around houses / buildings.

My question is on the topic of 120-volt pool lights - an inherently dangerous design where there are many points of failure that could lead to issue, especially as equipment (in a salt pool environment) ages and deteriorates.

I would like to upgrade my 120-volt pool lights to 12-volt. I know that I need an external, electrically isolated 120V AC to 12V DC transformer to power the new lights. However, I have some questions on the wiring and wiring safety:

1- The new lights are 12V DC, but for some odd reason, they still include a green grounding wire (some of them, the Pentair ones do - not sure about all of them). On "pool forums" people have been like "who cares, it's an extra wire, and it's probably there as a requirement so that if someone goes back to 120-volts in the future, then it's safe." Good thinking on the surface, but there is at least one incident where this green grounding wire was not connected to anything (because one doesn't need it on a DC circuit), and then the loose "grounding wire" became looser and contacted a 120-volt hot spot in the junction box and then energized the pool light housing and killed some kid in Florida. Very sad case: Google "Calder Sloan Swimming Pool" for more info (I'm not allowed to post links yet).

2- With that in mind, I think that it would be best (or code) to not mix the 12-volt wiring and 120-volt wiring in the same junction box? Right now, there is a big junction box with five "outputs" - three pool lights, a 120-volt outlet, and I think the fifth one powers the pool cover (not sure). If I don't update this myself, I'm thinking that I should insist that the electrician separate all of the 120-volt from the 12-volt physically with separate junction boxes? Is this code? It would seem like it would be for pool lights.

Thoughts would be appreciated - the typical Google search didn't produce anything useful or definitive.

-Wayne

 

[ajw22]

Welcome back to TFP.

It is code (NEC) to not mix high voltage and low voltage wiring in the same conduit or junction box. They must always be separated.

There are too many DIY projects that do not follow the NEC. We see them here all the time.

See NEC 680 for pool specific electrical codes.

A good reference is from Mike Holt Enterprises on Article 680—Swimming Pools, Spas, Hot Tubs, Fountains, and Similar Installations.

NFPA 70®, National Electrical Code® (NEC®), Now Used in All 50 States | NFPA

www.nfpa.org

 

[ajw22]

Right now, there is a big junction box with five "outputs" - three pool lights, a 120-volt outlet, and I think the fifth one powers the pool cover (not sure).

Show us pictures of this big junction box and your existing wiring.

 

[Jimrahbe]

an inherently dangerous design where there are many points of failure that could lead to issue, especially as equipment (in a salt pool environment) ages and deteriorates.

Wayne,

It is your pool and you should do what you want, but your statement is just not really true..

As long as the pool is bonded, and the AC to the light is from a GFCI source, there really is no big safety issue.

I suspect that on the list of things that you do everyday, that can kill you, getting electrocuted in a pool is way at the bottom of the list.

Thanks,

Jim R.

 

[Bperry]

Thanks in advance for input. My experience level is very high (mechanical engineer), but not to the level of a professional. I've done light switch replacements and simple fixes around houses / buildings.

My question is on the topic of 120-volt pool lights - an inherently dangerous design where there are many points of failure that could lead to issue, especially as equipment (in a salt pool environment) ages and deteriorates.

I would like to upgrade my 120-volt pool lights to 12-volt. I know that I need an external, electrically isolated 120V AC to 12V DC transformer to power the new lights. However, I have some questions on the wiring and wiring safety:

1- The new lights are 12V DC, but for some odd reason, they still include a green grounding wire (some of them, the Pentair ones do - not sure about all of them).

All light fixtures whether 120V or 12V need to be bonded and so that may be a reason for the “extra” wire. What does the installation manual for the light says it’s to be used for?

Like said above, the 120V system isn’t inherently more dangerous than the 12V as long as things are installed correctly. I still have 120V light in mine after I replaced it last year.

 

[JamesW]

The new lights are 12V DC, but for some odd reason, they still include a green grounding wire

What model lights?

Good thinking on the surface, but there is at least one incident where this green grounding wire was not connected to anything (because one doesn't need it on a DC circuit),

Low voltage pool lights are usually AC.

2- With that in mind, I think that it would be best (or code) to not mix the 12-volt wiring and 120-volt wiring in the same junction box?

Separate low voltage and high voltage.

 

[JamesW]

All light fixtures whether 120V or 12V need to be bonded and so that may be a reason for the “extra” wire.

Light niches have a bond terminal on the back/outside of the niche.

The inside terminal is for an extra ground wire and it is not required on "Listed" low voltage lights not requiring a ground.

 

[JamesW]

Rust from pool light ground wire

I had new Hayward Pool Light (non LED) installed last year. Shortly after, I noticed a streak of rust stains appearing above the light. The streak is easily cleaned with Vitamin C powder in a sock and being doing that every two - three weeks. I finally removed the light from the Niche to see...

www.troublefreepool.com

UL Listing required?

When replacing a light fixture that is in a wet niche, is the new fixture required to be UL Listed? I'm considering a fixture from sunseeker, but it is not UL. I would really like to go with the SS fixture, but don't want to do something wrong.

www.troublefreepool.com

 

[Bperry]

Light niches have a bond terminal on the back/outside of the niche.

The inside terminal is for an extra ground wire and it is not required on "Listed" low voltage lights not requiring a ground.

I’ll have to dig through my photos of mine. I seem to remember a wire terminal bonded to the inside of the fixture that led to the outside along with the others. But mine was 120V AC so that may have just been the ground terminal.

 

[JamesW]

(a) Metal Conduit. Metal conduit shall be approved and shall be of brass or other approved corrosion-resistant metal.

(b) Nonmetallic Conduit.

Where a nonmetallic conduit is used, an 8 AWG insulated solid or stranded copper bonding jumper shall be installed in this conduit unless a listed low-voltage lighting system not requiring grounding is used.

The bonding jumper shall be terminated in the forming shell, junction box or transformer enclosure, or ground-fault circuit-interrupter enclosure.

The termination of the 8 AWG bonding jumper in the forming shell shall be covered with, or encapsulated in, a listed potting compound to protect the connection from the possible deteriorating effect of pool water.

 

[JamesW]

The back terminal is for the bond wire.

The inside terminal is for a supplemental ground wire (aka a "Bonding Jumper").

120 volt lights have a ground wire in the cord and a supplemental ground is required because the NEC feels like the cord ground wire is too small.

The manufacturers lobbied against a requirement to increase the ground in the cord, so as a compromise, the NEC required a supplemental ground.

If a listed low voltage light does not require a ground, then the extra ground is not required either.

Why a low impedance bond from a wet-niche luminaire to its forming shell and pool bonding grid reduces the risk of electric shock.

The equipment grounding conductor in the flexible cord of the wet-niche luminaire may be relatively small (as little as 16 AWG in accordance with the NEC), and may have a length of one hundred feet or more.

The relatively small AWG and long length will result in increased impedance through the flexible cord equipment grounding conductor.

If the electrical bond between the luminaire and the forming shell is poor or absent, in an electrical fault condition within the luminaire this increased flexible cord impedance causes a relatively greater voltage potential between the dead metal of the luminaire and other dead metal connected to the premises’ equipment grounding conductor.

The supplemental equipment grounding conductor in the form of corrosion resistant metallic conduit connected to the forming shell or the 8 AWG copper conductor routed with the flexible cord in nonmetallic conduit provides a second, more conductive, path for fault current originating in the luminaire.

https://www.ul.com/global/documents/offerings/perspectives/regulators/electrical/newsletters/swimpool0803.pdf

Author’s Comment: The portion of the branch-circuit wiring to the pool junction box [680.23(F)(2)] shall contain a minimum 12 AWG insulated copper equipment grounding conductor.

The equipment grounding conductor between the pool junction box and the forming shell shall contain an 8 AWG insulated copper equipment grounding conductor [680.23(B)(1)].

A cord for a pool light run to the pool junction box shall have at least a 16 AWG equipment grounding conductor [680.23(B)(3)]. Figure 680-17 un680-17 680-23F2 02.cdr

Article 680 - Swimming Pool Installations

 

[JamesW]

The insulated copper equipment grounding conductor required with rigid nonmetallic conduit is terminated at an approved grounding terminal in the junction box (or transformer enclosure) and at the inside terminal of the grounding/bonding terminal on the fixture's forming shell.

This conductor has an equipment grounding function, not a bonding function.

It's in addition to, and of a completely different function than, the No. 8 bonding conductor usually connected to the external bonding lug.

The bonding conductor, which must be solid, connects the forming shell to the common bonding grid, as required by Sec. 680-22(a) and (b).

The No. 8 insulated copper equipment grounding conductor must be stranded, however. (Sec. 310-3 requires all No. 8 and larger conductors in raceway to be stranded.)

The two exceptions given do not apply here.

And it's important to also remember that Sec. 310-12(b) will normally require that the insulation be colored green.

Wiring wet-niche fixtures at the 1996 OLympics Aquatic Center. | Electrical Construction & Maintenance (EC&M) Magazine

 

[JamesW]

All light fixtures whether 120V or 12V need to be bonded and so that may be a reason for the “extra” wire.

The light or "luminaire" is the fixture.

The light is bonded by the screw that holds the light into the niche.

The niche is called a forming shell.

The niche can provide the water bond.

Metal niches are qualified and plastic niches usually have metal strips inside that qualify as a water bond.