What causes houses to catch fire from a hot tub?

(or How many hot tub sales people will even tell you about this?  The title should be:
"Just How Stupid are Spa Companies?" or  "That Fire Time Bomb In Your Back Yard.")

This subject of safety runs throughout our entire web site, because it is one of the  most important design concepts a consumer should consider. 

Steel and Aluminum Enclosures.

Every material used in the construction of electrical enclosures has a fire rating.  The worst is plastic with out fiber reinforcement.  The best is steel.
The steel that we use is similar to what is found in bar be que grills and gas or electric stoves.  It is also the same steel as used in your homes electric service panel.

If you were to go to Google Alerts and subscribe to "hot tub fires", you will see a pattern of hot tubs that catch on fire. The pattern is plastic boxes on older spas.
There have been 5 in the last six months according to the newspaper articles I have read.  There should be ZERO, if these spa manufacturers had any brains and used steel control boxes.  Those people's lives are threatened by this, (and as I do more research on this, I'll bet people have died from this.)

Here is what happens inside those boxes, because I have seen this many times.  The power lugs coming into the spa pack corrode and arc, or circuit board relay starts to fail, it starts arcing like a welder and the arc melts through the plastic and starts the spa on fire.  Then the spa starts the deck on fire and then the house.

With steel, the arc never gets outside the enclosure.  I have seen this on three of our Haven Spas in the last 9 years.   Most always it is from the electrician, not connecting the power wires to the spa correctly.
They must be tightened and then as the strands compress and settle under the lug, tighten them again to take all the "slack" out of the strands.  The strands literally move out as the lug is tightened and it can fool you into thinking it is tight. Go back in a few seconds and you can tighten it more, because the strands settle "like spaghetti" as they spread out.  Also in wet areas along the coast, you must use an anti-oxidant on the wires or have someone check them every few years for corrosion. Corroded main lugs start fires.

There is no qualified electrician in the US who is allowed to use plastic load centers in your home next to flammable materials.  So why is the load center of a 50 or 60 AMP spa allowed to be made from plastic?

There is no qualified electrician in the US who is allowed to use plastic load centers in your home next to flammable materials.  Not only is it not a good idea, IT IS AGAINST THE LAW.  So why is the load center of a 50 or 60 AMP spa allowed to be made from plastic?   It is because of profits and companies who are only concerned about money and not concerned about a statistic of someone's home being destroyed, "once in a while".

Every time I have seen a burned out control box made from steel, you cannot tell from the outside of the box what is inside.  The outside looks all clean and white, with no signs of electrical arcing.
When I opened up the box, then I can see all the black and burned out electrical parts.  With plastic, you mostly can't even tell where the box is or even what it was, after the fire, because as the deputy fire marshall told me, he could not even tell what "that black charred thing was" with the wires coming to it was.  This was after they put the fire out and the spa burned the deck and almost burned the house down.
If the owner had not been home, he would have no house to come home to.

I can't stress how idiotic it is to use a plastic enclosure on high current spa boxes.   Plastic main boxes are a "time bomb" waiting to start fires "down the road".

If you understand electricity at all, a steel control box or aluminum is a grounded metal enclosure that shields the electronics from outside radio waves or any magnetic influences.  It also, AND THIS IS VERY IMPORTANT TO UNDERSTAND, grounds out the arc from any electrical connector that touches it and IMMEDIATELY TURNS OFF THE POWER TO THE SPA, because the Ground Fault Protection, trips immediately.

With plastic, the GFCI does not trip, because it is not a conductor, so the arc keeps on going, melts and penetrates outside the plastic box.  I can't even begin to tell you how dangerous that is on an old spa.  As the wires ages and start to have corrosion it will eventually break the connection and create a "distance" between the connection.  When the electricity is turned on, it jumps that small gap and gets very hot.  It melts the wires and creates an even bigger gap that becomes a bright "arc lamp".  If it were to contact metal the arc would shut off the GFCI..  If it contacts plastic, it melts the plastic and starts arcing on the outside of the box and the plastic will start to burn, even if it has flame retardant in it, because it is a "petroleum" product.  

The second best is aluminum, but it still has a much lower resistance to fire escape than steel.  But with the advent of the GFCI Aluminum is OK

Why take the chance.  We only use metal control boxes on Haven Spas; Aluminum on some models with less current.



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