Reptile & Amphibian Forums

Do the Helix controls proportional thermostats accept a grounded plug (3 prong) from the heat source?
-----
Chris Harrison

...he was beginning to realize he was the creature of a god that appreciated the discomfort of his worshippers - W. Somerset Maugham

The Helix Basic model does. I don't know about the newer DS1000 or whatever that model is (the least expensive one.)

What kind of heater? For resistive heaters like heat mats (Kane heat mats for example have a 3-prong plug) you can get away with using a 3-to-2 prong adapter.

Hi Mark,

I only have a basic understanding of this. Could you summarize what heat sources are safe to use with 3-to-2 prong adaptors and which are not?

Are all non-resistive heat sources unsafe to use with these adaptors?
**************
For resistive heaters like heat mats (Kane heat mats for example have a 3-prong plug) you can get away with using a 3-to-2 prong adapter.

Oh never mind me.. what I meant to say is any heater that doesn't have a grounded case or say fans, motors, etc like room space heaters. Any heat pad, Flexwatt, heat cable or bulb is fine with a 2-prong polarized plug (actually, Flexwatt and heat pads do not even require a polarized plug, but all bulb sockets do for protection to you - you don't want the threaded shell to be live AC because it is within touching distance when you screw in a bulb. A polarized plug ensures that the shell is connected to the neutral wire.) I've been using a Kane heat mat with a 3-to-2 adapter for years with no problems, and Kanes come with a 3-prong cord.

Thanks Mark.

How about oil-filled space heaters?

A friend of mine used an old Biostat Thermostat (with only a 2-pronged outlet) and then plugged a multi-strip into it, using a 3-to-2 prong adaptor.

Into the multi strip he plugged an oil-filled space heater (3 prongs) and a box fan.

The thermostat failed and I'm wondering if it was due to exceeding the wattage limitations of the thermostat or due to a grounding issue?

I do not know the wattage limitations of the biostat. It is not listed on the product nor did anything turn up in a Google search.

Any thoughts?

The failure was most likely not a grounding issue. The grounding is there for safety, not function. Should a hot wire touch the case, the circuit breaker blows. With no grounding, the case would just be live as well and shock you if you touched it.

I bet the failure was a wattage issue. Those Biostats are made for low-wattage heaters like heat pads, not room heaters or fans. Fans have an in-rush current that is very high. Yep. He did a bad thing.

That's what I thought as well but thought I'd double check since the topic came up.

Fortunately the biostat simply stopped supplying power to the heater. It still cycled (the power light kicks on if you turn the dial way up and off if you turn it down) but simply did not power the multi-strip.

I even plugged in a low wattage lamp and it would not run that either. He obviously trashed the thermostat.

It probably blew the output device only, or else there is an on-board fuse. If you wanted, you could replace the damaged component and have a working T-stat again.

FYI, sometimes a solid-state output device will fail ON if overloaded. Proportional devices use solid-state relays. Tell your friend to never overload a Helix or Big Apple proportional (although I think both have fuses for protection.)

Excuse me Chris for chuckling.. he attached a room heater and a fan to the little Biostat.. hee hee hee ho ho ha ha. Seriously, the outcome could have been worse. Thank goodness for fuses, melted contacts or blown transistors, whichever it was.

What kind of heater? For resistive heaters like heat mats (Kane heat mats for example have a 3-prong plug) you can get away with using a 3-to-2 prong adapter.

I am considering getting one to use with an oil-filled heater as a failsafe in a brumation room/garage. I have heard horror stories about the lousy thermostats in those heaters.

For heat tape, I don't use proportional thermostats. I simply use a cheap on/off thermostat and a dimmer switch. Basically the thermostat is there to turn the heat tape off if the temp in the room gets too high, and the dimmer prevents the heat tape from getting too warm.
-----
Chris Harrison

...he was beginning to realize he was the creature of a god that appreciated the discomfort of his worshippers - W. Somerset Maugham

Not exactly what you were asking -

I've got two Lakewood oil-filled heaters (the 600 and/or 900 watt type). They have a two-prong plug, not three.

I've been using this type of heater since the late 1970's without a failure in any of their thermostats. But, of course, the wide range of their on-off temps is lousy. Also, some of the original models leaked oil! Glad they fixed that. I do like them better than the fan-forced air type.

-Joan

Good idea for a backup thermostat. You can surely go with an ON/OFF thermostat for this application. After all, it is a failsafe more than a temperature maintenance application. A Ranco is a great choice. I have one from www.herpsupplies.com, about $60. It does take some wiring, but it isn't difficult, and you may easily include the ground wire. I believe the Boaphile sells these wired and ready to go for 3-prong plugs. Check www.boaphile.com.

All ON/OFF t-stats have a temperature differential. The less expensive models have a built-in differential of around 4 degrees usually. That is, the device might shut off the heater at say 80 deg, and turn on again at 76 deg roughly. Anyway, Rancos have an adjustable differential down to 2 deg. This is plenty tight control for room ambient air. Home thermostats aren't even that tight usually (and for good reason - you don't want your home air cond cycling ON and OFF too often. The startup current is huge and costs money, and the compressor and fans wear out sooner.)

I've used an inexpensive thermostat available at farm supply stores for my oil-filled space heater. It's been trouble free for years and is rated for 3000 watts, I believe.