Pool light junction box

[blkmagik21]

We use that Intermatic PJB exclusively. Intermatic also has a common mounting bracket for the 2 versions of this model. This allows for mounting on a surface such as a wall or 6x6 post, etc...
They also just came out with a model that has a built in 100w transformer. So no need for a separate transformer.

Like others responding on this post, it has a ground bar built in. It also has a bond lug.

The other feature this box has, as do other listed pool/spa boxes, it has a cord restraint which I'm pretty sure is a code requirement.

I’ve never seen the junction box with the transformer built in. This changes everything! Lol

I have usually went from the panel to a transformer then conduit from there to a 3r gutter. Then out from there to all my low voltage led pool lights. I use the gutter because some of the pools I’m doing have around 15-20 led lights.


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[Little Bill]

As a general rule I don't do swimming pool electrical work so that's why I asked about the # 8 solid in the wet niche. So, let me understand - the deck box includes a # 8 solid from the wet niche, a # 8 solid from the equi-potential bonding grid, a 14/2 S/O cord from the light fixture and # 12's from the breaker panel and/or switch. It all makes sense now.:blink:

The #8 from the JB to the inside of the niche is not a solid conductor. It has to be an insulated #8.
The solid (bare) does not go into the JB. It just goes from the back of the niche to the bonding grid.

 

[nizak]

I wonder if the circular mil of the stranded #8 is oversized to account for possible deterioration of the wire inside the niche over time.

It really doesn't make much sense since the E.G. To the j box is usually #12.

 

[david]

The #8 from the JB to the inside of the niche is not a solid conductor. It has to be an insulated #8.
The solid (bare) does not go into the JB. It just goes from the back of the niche to the bonding grid.

Is that a code change 2011 , 14 ,17

(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

 

[david]

As a general rule I don't do swimming pool electrical work so that's why I asked about the # 8 solid in the wet niche. So, let me understand - the deck box includes a # 8 solid from the wet niche, a # 8 solid from the equi-potential bonding grid, a 14/2 S/O cord from the light fixture and # 12's from the breaker panel and/or switch. It all makes sense now.:blink:

Not exactly, the deck box is only required one provision for a # 8.

The min size equipment ground for swimming pools is a #12 Copper unless low voltage, the min size bonding conductor is a # 8 the insulated green # 8 from the pool deck box to the inside of the nitch is defined by the NEC as a bonding conductor

 

[Little Bill]

Is that a code change 2011 , 14 ,17

(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

I was trying to say that the conductor (bonding jumper) had to be insulated. I should have used the word (bare) when I said "The #8 from the JB to the inside of the niche is not a solid conductor".
I was trying to differentiate between the insulated #8 bonding jumper from inside the niche and the bare #8, jumper to the grid [lack of a better term] on the back of the niche that runs to the bonding grid and not to the JB. The OP was saying both the bonding jumper (insulated #8) and the grid jumper (bare #8) went in the JB. The insulated jumper is the only one of the two that goes in the JB.

 

[Mystic Pools]

I’ve never seen the junction box with the transformer built in. This changes everything! Lol

I have usually went from the panel to a transformer then conduit from there to a 3r gutter. Then out from there to all my low voltage led pool lights. I use the gutter because some of the pools I’m doing have around 15-20 led lights.


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I saw the new j box at the swimming pool show in January. It's perfect for when we build a pool/spa combo and have one nichless LED light for the spa. https://www.intermatic.com/en/pool-and-spa/junction-boxes/pjbx52100

For the pools, we generally have a minimum of 4 lights (could be 20w or 30w model all nicheless) which requires a 300w transformer. I had asked if a 300w built in model was available-no such luck.
Intermatic does offer a 600w transformer which is great for jobs with lights exceeding say (12-13) @20watt. https://www.intermatic.com/en/pool-and-spa/transformers/px600

 

[david]

I was trying to say that the conductor (bonding jumper) had to be insulated. I should have used the word (bare) when I said "The #8 from the JB to the inside of the niche is not a solid conductor".
I was trying to differentiate between the insulated #8 bonding jumper from inside the niche and the bare #8, jumper to the grid [lack of a better term] on the back of the niche that runs to the bonding grid and not to the JB. The OP was saying both the bonding jumper (insulated #8) and the grid jumper (bare #8) went in the JB. The insulated jumper is the only one of the two that goes in the JB.

makes sense.

 

[david]

Aside from "that's what the Code says" I don't understand why the # 8 is required from the wet niche to the deck box when the circuit feeding it is run with # 12.

It all ties to the equipotential bonding at some point so that would be the only reason I know.

Remember the code also requires the equal potential bonding grid to bond with a # 8 to a branch circuit # 12 equipment ground at some point. The # 8 bond from the pool j box to the nitch is one place that this connection is accomplished.

The other common place for this connection is at the pool pump.

 

[Strathead]

I wonder if the circular mil of the stranded #8 is oversized to account for possible deterioration of the wire inside the niche over time.

It really doesn't make much sense since the E.G. To the j box is usually #12.

That is because you are looking at it incorrectly. The #12 is sized as it is to allow sufficient current flow to trip the circuit breaker in event of a ground fault. The #8 is part of the pool bonding system that is designed to keep ALL METAL ITEMS within the pools perimeter at the same potential so someone doesn't receive a shock or current flow from anything. It isn't an equipment ground, it is a pool bonding jumper.

 

[david]

That is because you are looking at it incorrectly. The #12 is sized as it is to allow sufficient current flow to trip the circuit breaker in event of a ground fault. The #8 is part of the pool bonding system that is designed to keep ALL METAL ITEMS within the pools perimeter at the same potential so someone doesn't receive a shock or current flow from anything. It isn't an equipment ground, it is a pool bonding jumper.

That is not exactly correct the insulated # 8 from the pool deck box to the nitch provides an equipment ground bond to a metal light trim ring if a plastic trim ring is not used or is replaced with a metal trim ring

That is why it is required to be green in color and is required to be insulated the same as all equipment grounds for pools.

think of it as a duel purpose conductor bond / equipment ground

 

[david]

Used wirenut

This is a common mistake never use wire nuts on the equipment ground for the branch circuit for a light fixture for a swimming pool

: "on grounding terminals (not wire nuts)
" or an outlet box used to enclose a snap switch."

(b) If the underwater luminaire is supplied from a transformer, ground-fault circuit interrupter, clock-operated switch, or a manual snap switch that is located between the panelboard and a junction box connected to the conduit that extends directly to the underwater luminaire, the equipment grounding conductor shall be permitted to terminate on grounding terminals on the transformer, ground-fault circuit interrupter, clock-operated switch enclosure, or an outlet box used to enclose a snap switch.

 

[Strathead]

That is not exactly correct the insulated # 8 from the pool deck box to the nitch provides an equipment ground bond to a metal light trim ring if a plastic trim ring is not used or is replaced with a metal trim ring

That is why it is required to be green in color and is required to be insulated the same as all equipment grounds for pools.

think of it as a duel purpose conductor bond / equipment ground

I don't agree. You don't run a #8 to the panel. It may act that way, but I don't believe it is installed for that purpose.

{edit} but I am speaking out of butt here, for the record. Just speculating.

 

[david]

I don't agree. You don't run a #8 to the panel. It may act that way, but I don't believe it is installed for that purpose.

{edit} but I am speaking out of butt here, for the record. Just speculating.

Actually you are required to bond the equal potential bonding grid with a # 8 bond to the pump and is required to bond through that connection to the #12 equipment ground.

If that connection is not made at the pump location you are required to insure that # 8 bond to a # 12 equipment ground at some other location.

As i stated the #8 insulated green bond from the pool deck j box to the encapsulated connection in the nitch by the stud that connects directly to the # 8 bond on the back outside of the nitch is the other common location this required connection is made

Also this duel purpose # 8 green insulated conductor serves as an equipment ground bond to the metal trim ring for the light fixture

680.26 Equipotential Bonding.

(a) Double-Insulated Water Pump Motors.
Where there is no connection between the swimming pool bonding grid and the equipment grounding system for the premises, this bonding conductor shall be connected to the equipment grounding conductor of the motor circuit.

 

[david]

680.6 Grounding. The following equipment shall be grounded: (1) Through-wall lighting assemblies and underwater luminaires, other than those low-voltage lighting products listed for the application without a grounding conductor
(2) All electrical equipment located within 1.5 m (5 ft) of the inside wall of the specified body of water
(F) Branch-Circuit Wiring.

In all cases, an insulated equipment grounding conductor sized in accordance with Table 250.122 but not less than 12 AWG shall be required.

The trim ring as part of the light fixture as part of electrical equipment with in 5 feet of the pool water is required a min of a #12 green insulated equipment ground bond.

The # 8 green insulated bond from the pool j box to the nitch meets those min requirements

 

[david]

I don't agree. You don't run a #8 to the panel. It may act that way, but I don't believe it is installed for that purpose.

{edit} but I am speaking out of butt here, for the record. Just speculating.

Can you explain why the # 8 bond from the pool deck j box to the light fixture nitch is required to be green in color and required to be insulated if it is not also intended to be viewed as meeting the requirements for a swimming pool
branch circuit equipment ground

yes the NEC defines it as a bonding conductor (jumper) but also gives it the necessary min requirements of a require pool branch circuit equipment ground.

I would think of it as a duel purpose conductor bond / equipment ground

 

[Strathead]

Can you explain why the # 8 bond from the pool deck j box to the light fixture nitch is required to be green in color and required to be insulated if it is not also intended to be viewed as meeting the requirements for a swimming pool
branch circuit equipment ground

yes the NEC defines it as a bonding conductor (jumper) but also gives it the necessary min requirements of a require pool branch circuit equipment ground.

I would think of it as a duel purpose conductor bond / equipment ground

It could be merely a corrosion issue. It doesn't"meet" the requirements it exceeds in two ways. insulated and large. Can you explain why it is a #8?

 

[david]

It could be merely a corrosion issue. It doesn't"meet" the requirements it exceeds in two ways. insulated and large. Can you explain why it is a #8?

If you want the short answer the min size for a pool bonding conductor is required to be a #8 copper AWG and the NEC defines this conductor as a bonding conductor.

The other reason i did explain when the pool deck j box uses a wire type bond not a conduit type brass or other approved metal conduit from the grounding terminals in the listed pool deck box to the nich making the required connection from the equal potential bonding grid to a branch circuit equipment ground this min size bond to the 12 Gage copper equipment ground is required to be a # 8 bonding conductor

the other thing i would have you consider is the grounding at patient care areas heath care facilities, when the human body is exposed to greater risk of electrical shock the Code takes additional measures to lower the risk.

In the swimming pool the additional risk would be at the lighting fixture in contact with the exposed body through the water. The code took a additional measures by increasing the safety at the light fixture rather than requiring a metallic conduit equipment ground allowed a PVC conduit as long as the equipment ground bond was increased in size from a min #12 to a min #8

 

[david]

It could be merely a corrosion issue. It doesn't"meet" the requirements it exceeds in two ways. insulated and large. Can you explain why it is a #8?

the corrosion is supposed to be addressed by a listed potting compound