Portable hot tubs - Protect conductors from physical damage

[HotTubTips]

1

 

[ramsy]

Yes, that bothers me too. I carry these plastic bushings in my truck, but grommet, or even tape could protect those conductors.

Unfortunately, quoting code is not likely to get someone back for a Warranty call, until it trips the GFCI.

Perhaps carry some bushings yourself, and charge your time & material.

 

[LarryFine]

In my opinion, the wiring method (cable, flex, etc.) should be continued all the way to the box and the correct connector installed in that knockout

 

[hbiss]

In my opinion, the wiring method (cable, flex, etc.) should be continued all the way to the box and the correct connector installed in that knockout

That's the first thing I noticed! The conductors shouldn't be exposed at that point to begin with, never mind a bushing. Somebody had no clue how to wire that.

-Hal

 

[HotTubTips]

Thanks Ramsy and I do sometimes fix simple issues but the photo above was just one of several more serious problems. That tub also had no GFCI and the maintenance disconnect was less than 1 foot from the tub so even a child could touch it while sitting in the water. I provide a complete inspection report that lists all the problems including code citations. The customer has to fix at least the most serious problems before I'll complete a repair. If they refuse...I walk away from the job. I'm busy enough with tubs that are wired right that I don't need to risk working on one with serious hazards. I've had pretty good luck convincing people to make it safe. If they refuse...they can call somebody else to fix the tub.

 

[HotTubTips]

Thanks Larry. That's my opinion too and I usually see flexible, liquid tight conduit with waterproof fittings all the way to the control box.

f you look close at the photo, the plywood under the control box is starting to rot and is crusty with scale from previous leaks so those wires were surely wet for weeks or months.

Hot tubs in San Diego also attract rats and I've seen tubs with the insulation chewed off the wires exposing bare copper.

 

[jap]

The wire is more than likely wet location rated anyway so that's not as big a deal as not having a connector or a bushing through the KO.

A GFI is probably not going to react fast enough to keep the wiring from shorting out to the enclosure if the metal happens to rub through the insulation.

JAP>

 

[HotTubTips]

Thanks jap. As I understand it: THHN can be used in dry and damp locations. THWN can be used in wet locations but still must be protected from physical damage such as me dragging a 40 to 50 lb pump out of a very confined space or rats chewing on wires.

A big question is whether code considers the equipment area of a portable hot tub as normally 'dry location', sometimes 'damp location', or sometimes 'wet locaiont'.

My experience is: should be dry, often damp, sometimes wet, sometimes flooded or submerged and sometimes corrosive if people store chemicals inside the cabinet of the hot tub.

Since I get wet almost every day working on them, I consider the equipment space to be a 'wet working space'. I keep a 18V leaf blower on my van just for drying out things that accidentally get sprayed or splashed in the normal course of fixing things. The pump motors are NEMA 'drip proof' or 'splash proof' and even the circuit boards are dipped and sealed in varnish so everything about the design and UL, CSA or ETL Listing suggests 'wet location'.

In the system pictured above, if the wire shorts to the metal box, a GFCI breaker should trip instantly. If you look close you'll see a green machine screw sticking up through the box. That's one of four screws and two clamps that hold the stainless heater manifold to the aluminum control box.

More importantly, the heater manifold is also a current collector. If the heat element inside the manifold shorts to the water you're soaking in, the grounded manifold that contains the heat element is the shortest path to ground. If everything is wired properly and assembled properly, the GFCI will trip immediately. That's why little details like the heater mounting screws are so important. The stainless heater manifold, the aluminum straps and machine screws that secure the heater manifold to the aluminum control box are all part of the chassis ground.

In most portable hot tubs, L1 is hot to the heat element as soon as the breaker is turned on. L2 or Neutral is switched to make the heater turn on or off. L1 always hot means a heat element short will trip the GFCI as soon as you try to turn it on meaning a heat element short trips the breaker immediately rendering the hot tub unusable until you replace the element.

Bad pun but it's 'shocking' how many tubs I see that are essentially electrocutions waiting to happen. I frequently tell my customers a portable hot tub is the only appliance you bring home, connect to electricity, fill with water and then climb inside so you can sit in water up to your neck that's connected to 220V. When Handy Andy Homeowner wants to argue about an obvious electrical hazard...I know I'm talking to the person who wired it and I sometimes wonder if I'm interfering with natural selection.

 

[jap]

Thanks jap. As I understand it: THHN can be used in dry and damp locations. THWN can be used in wet locations but still must be protected from physical damage such as me dragging a 40 to 50 lb pump out of a very confined space or rats chewing on wires.

A big question is whether code considers the equipment area of a portable hot tub as normally 'dry location', sometimes 'damp location', or sometimes 'wet locaiont'.

My experience is: should be dry, often damp, sometimes wet, sometimes flooded or submerged and sometimes corrosive if people store chemicals inside the cabinet of the hot tub.

Since I get wet almost every day working on them, I consider the equipment space to be a 'wet working space'. I keep a 18V leaf blower on my van just for drying out things that accidentally get sprayed or splashed in the normal course of fixing things. The pump motors are NEMA 'drip proof' or 'splash proof' and even the circuit boards are dipped and sealed in varnish so everything about the design and UL, CSA or ETL Listing suggests 'wet location'.

In the system pictured above, if the wire shorts to the metal box, a GFCI breaker should trip instantly. If you look close you'll see a green machine screw sticking up through the box. That's one of four screws and two clamps that hold the stainless heater manifold to the aluminum control box.

More importantly, the heater manifold is also a current collector. If the heat element inside the manifold shorts to the water you're soaking in, the grounded manifold that contains the heat element is the shortest path to ground. If everything is wired properly and assembled properly, the GFCI will trip immediately. That's why little details like the heater mounting screws are so important. The stainless heater manifold, the aluminum straps and machine screws that secure the heater manifold to the aluminum control box are all part of the chassis ground.

In most portable hot tubs, L1 is hot to the heat element as soon as the breaker is turned on. L2 or Neutral is switched to make the heater turn on or off. L1 always hot means a heat element short will trip the GFCI as soon as you try to turn it on meaning a heat element short trips the breaker immediately rendering the hot tub unusable until you replace the element.

Bad pun but it's 'shocking' how many tubs I see that are essentially electrocutions waiting to happen. I frequently tell my customers a portable hot tub is the only appliance you bring home, connect to electricity, fill with water and then climb inside so you can sit in water up to your neck that's connected to 220V. When Handy Andy Homeowner wants to argue about an obvious electrical hazard...I know I'm talking to the person who wired it and I sometimes wonder if I'm interfering with natural selection.

You cant consider a location an "NEC wet" location just because of silly human interaction.

If that were the case, we could use the most times dry, sometimes damp, a few times wet and occasionally corrosive on most every aspect of electrical installations.

There's a difference between a GFI tripping because of small current leakage and a full blown Ground Fault or Short Circuit.

If those conductors short to the aluminum housing of the controls, the GFI feeding it should trip, yes, but will trip because of the short circuit condition, not the gentle trip you get from pushing the test button.

Regardless, if the unit comes with exposed wiring from the factory it's one thing, but, as far as the field wiring that the contractor installs, there are rules for protecting the conductors from damage, and, completing raceway systems.


JAP>

 

[al hildenbrand]

I frequently see #8 THHN connected to portable hot tub control boxes without conduit or fittings at the control box entry point (see photos).

In some cases, the control box is metal and the THHN is allowed to rub on the metal edge of the entry point. The pumps in the tub create vibrations that will eventually lead to insulation damage. The interior space of the hot tub equipment area is normally dry but potentially wet if a fitting breaks or something leaks or when a hot tub owner must bleed air from the plumbing when they prime the pump.

I usually cite 300.4 'protection from physical damage' but I'm looking for other code citations I can use to force correction of this problem.

Some electricians have argued the inside of a portable hot tub is a protected space that doesn't require conduit. I believe it's a working space where conductors could be damaged when I'm removing or replacing a pump or other parts.

I think 300.18(A) is more to your liking.

The "field installed" wiring is regulated by the NEC all the way "Outlet" as defined in Article 100 Definitions. In the photo shown, the "Outlet" is the end of the THHN conductors under the terminal block terminal screw. By 300.18(A), the branch / feeder circuit conductors have to be in a complete raceway ending at a junction box.

The wiring in a hot tub assembly that is provided from the manufacturer is NOT regulated by the NEC directly, but rather by the manufacturing and Nationally Recognized Testing Laboratory standards that apply. One cannot compare factory wiring to field installed wiring.

 

[HotTubTips]

Thanks al. Adding 300.18(A) to my website right now.

 

[HotTubTips]

Thanks to everybody for all the helpful input. Here is the finished page I'll use when explaining problems to my customers: http://affordablehottubrepair.com/hot-tub-electric-code-conduit.html

 

[Dennis Alwon]

I have done many of these installs and there is no way that is compliant. The flex needs to extend all the way to the unit ko's. Heck protection from damage should be all you need but then they would just use a bushing. 300.18, as stated, definitely applies..