Scientific Oven not so Scien-terrific

[greenbank]

I picked up a smallish Thermo scientific oven from CL ages ago to bake enamel-painted parts in...the max 200-degree temp is perfect for that and it doesn't take up a ton of space.

My problem is this: I finally set it on the bench and plugged it in the other day, and it trips my GFCI outlet after about a minute. It does that predictably. I have a plug-in meter which I can plug the oven into, and it was drawing a steady 6.6 amps, on a 20 amp circuit.

My other problem is that every 115 outlet in my shop is protected by a GFCI. So I don't really have the option of just plugging it into a "plain" circuit, nor do I want to, I guess, if it's got an issue.

So: Is this typical of this sort of appliance, and not designed to be plugged into a GFCI, or is there something wrong with the oven itself...and if so, any good places to poke? I don't have a lot of money into this and don't plan on having a lot into it, so if it's not good and not cheap to fix, I'll move it along.

But it sure would be nice to have it working.

 

[mrb]

there is something wrong with the oven. the GFCI is keeping it from shocking you. Is there anything else on the GFCI in addition to the oven? What changes on the oven at the point the GFCI trips? Does it have a motor that turns on?

 

[MBfreak]

If the oven use a Infra Red heat source, they are quite prone to develop earth faults as the "ceramic" heat radiating element gets hot.

Probably hard to find a spare. If you find one, just replace the IR radiator and you will be OK

Ola

 

[Alchymist]

Take an ohmmeter and check the line cord. Ground pin to chassis - "0" ohms, (continuity). Line and neutral to chassis - infinite (no continuity). Any thing else is a problem. Find the wire (hot or neutral) that rings to chassis and trace it out to where it makes a contact to the chassis. Worst case is an element replacement, but could be anything.

 

[mrb]

Take an ohmmeter and check the line cord. Ground pin to chassis - "0" ohms, (continuity). Line and neutral to chassis - infinite (no continuity). Any thing else is a problem. Find the wire (hot or neutral) that rings to chassis and trace it out to where it makes a contact to the chassis. Worst case is an element replacement, but could be anything.

thats a place to start but is not definitive. there could be broken down insulation that doesnt leak current at the low voltage of an ohmmeter. Also could be something in the oven that isnt connected to the line input when the oven isnt running.

 

[greenbank]

Thanks for the ideas. I'll throw an ohmmeter on it next time I get a chance, just to see.

Far as I can tell, there is a typical "electric range" type element inside the box. I was imagining that what clicks in after a minute or so (and trips the outlet) is some sort of switch/relay that turns the element off, as it doesn't take very long to heat an insulated dorm-fridge sized box to 200 degrees. But I haven't had time to look, yet.