Leakage to chassis is normal. If its only a few milliamps, then it is probably safe. Underwriters Laboratories requires 100% leakage testing on most AC operated consumer appliances (maybe all of them), so if your rotisserie has a UL label and the safety was not compromised by your repair you are probably ok.

Edit: (add) A GFIC probably wouldn't hurt; I use them on non-grounded appliances indoors and out.

Using a three wire power plug and connecting the earth wire to the chassis will reduce the chance of shock or annoying tingle when the appliance is touched (I did this with my refrigerator and computer -neither came with a three conductor cord).

You can measure the leakage current from the chassis to earth by running a wire between earth and the chassis and inserting a 1.5k resistor shunted with a .15 uf capacitor, then measuring the AC voltage across the resistor and calculating the current through it.

View attachment 83177

For safety, in your test, only connect your meter and shunt (R and C) to earth and not to Neutral.

View attachment 83178
The images above are from the publication at the URL below (Electrical Safety Testing Reference Guide). It contains a good tutorial on the subject.
www.psma.com/ul_files/forums/safety/estguide2.pdf

Excellent information. If I can scrounge up those components I may try your suggestion just to possibly learn something. In the mean time I've gone ahead and ordered another heater element. I am almost sure that is where the problem is. Thanks for the info.

 

Are you saying this is a "double insulated " appliance? Should have a little double square on the label indicating such. If so it does not need to (and usually cannot be earthed) since there is no external metal
Although if you can reach the internal metal element this should only be when power off and isolated.

I will look for the double square. I don't know if it is double insulated. But I do know the outer surface is either some kind of painted metal or plastic. The only exposed metal is inside the appliance. I ran my meter all around the exterior and could not detect any voltage. If I can eliminate the voltage floating on the chassis interior, I may go ahead and install a 3 conductor power cord. Thanks for your feedback.

 

Today I received the "new" heater element. It's not actually new because there are no new elements available so I bought a used one through Ebay. Using my Fluke 87 meter, I compared resistances between the two heater elements. I have not installed the new element yet. Total resistance for the new element is 11.8 ohms. That equals about 10 amps at 120 VAC. Of course, 10 amps at 120 VAC equals 1200 watts. The old element measures the same 11.8 ohms from tip to tip. So far so good. Here's where it gets strange. If I measure from one terminal (either one) to the outer tube of the element, the two elements are VERY different. The old element measures 9.5 M ohms while the "new" element measures 280 K ohms. The old element has 34 times more resistance between the internal conductor and the outside tube. I don't have a lot of experience with heater elements so I'm not sure if this is an issue or not. I will install the new element and carefully measure for any leaking voltage in the chassis of the appliance.

I would love to have a brand new heater element that I could compare these readings to. Because I now have two elements that may have their own problems. In theory, I would think the resistance between the conductor and the outer tube would be infinite. I guess there could be some conductivity through the insulator that would prevent an infinite reading.

Any comments on this situation would be appreciated.

Thanks,
Greg / Canyon Lake, CA.

 

Infinite resistance is really hard to measure accurately

Seriously, if everything is well insulated you will probably still see "leakage voltage" if you use a typical DVM with a high input resistance.

What would be useful is the leakage current. This is done by making a shunt of a 0.15 uf nonpolarized capacitor in parallel with a 1.5k resistor, putting the shunt between your cooker and earth, and measuring the AC voltage across the shunt. If you get over 375 mv RMS (according to the UL recommendation) your leakage current is excessive.

Earthing the appliance can't hurt and may save somebody's life.

 

Infinite resistance is really hard to measure accurately

Seriously, if everything is well insulated you will probably still see "leakage voltage" if you use a typical DVM with a 10 Meg input resistance. What you should probably measure is leakage current instead. This is done by making a shunt of a 0.15 uf nonpolarized capacitor in parallel with a 1.5k resistor, putting the shunt between your cooker and earth, and measuring the AC voltage across the shunt. If you get over 375 mv RMS (according to the UL recommendation) your leakage current is excessive.

Earthing the appliance can't hurt and may save somebody's life.

Thanks for the advice. I doubt if I have the specific components you recommend. Instead of the shunt, what if I just run a jumper wire to ground and see if the GFI trips? Do you happen to know how many milliamps or microamps would trip the GFI?
If I can get it to run without tripping the GFI while the chassis is grounded, I will upgrade the power cord to a 3 conductor just to be safe.

If it still trips the GFI, I will toss the whole thing in the trash.

 

Today I received the "new" heater element. It's not actually new because there are no new elements available so I bought a used one through Ebay. Using my Fluke 87 meter, I compared resistances between the two heater elements. I have not installed the new element yet. Total resistance for the new element is 11.8 ohms. That equals about 10 amps at 120 VAC. Of course, 10 amps at 120 VAC equals 1200 watts. The old element measures the same 11.8 ohms from tip to tip. So far so good. Here's where it gets strange. If I measure from one terminal (either one) to the outer tube of the element, the two elements are VERY different. The old element measures 9.5 M ohms while the "new" element measures 280 K ohms. The old element has 34 times more resistance between the internal conductor and the outside tube. I don't have a lot of experience with heater elements so I'm not sure if this is an issue or not. I will install the new element and carefully measure for any leaking voltage in the chassis of the appliance.

I would love to have a brand new heater element that I could compare these readings to. Because I now have two elements that may have their own problems. In theory, I would think the resistance between the conductor and the outer tube would be infinite. I guess there could be some conductivity through the insulator that would prevent an infinite reading.

Any comments on this situation would be appreciated.

Thanks,
Greg / Canyon Lake, CA.

The fault in the 'old' element may occur only while (thermally) hot and/or with line "voltage" applied --- That said, I'm less than 'enthusiastic' about the (conductor-to-jacket) resistance (280K) of the 'new' element -- while (assuming a worst-case 'leak' near the electrically 'hot' end) 430uA isn't generally dangerous, you'd feel it, and, more importantly, inasmuch as it represents an 'out of Spec'. condition, it may be indicative of 'a failure in progress', as it were...

Without wishing to 'whip' the proverbial 'dead horse' I strongly recommend that you find a way of properly grounding the chassis! While GFCIs are necessary and efficacious life saving devices, hazard avoidance, where possible, is always preferable to mitigation...

Best regards
HP

PS

If it still trips the GFI, I will toss the whole thing in the trash.

...And spoon-feed the 'new' element to the Ebay 'seller'

 

Well, I finally got around to installing the so-called "new" heater element. As I expected, I measured about 113 VAC from chassis to ground when the rotisserie is running and the heater element is energized. I repeated the bulb test where I create a path through the bulb to see if the GFI trips. It tripped immediately. So, taking the advice I got from this forum, I repeated the bulb test using a power outlet NOT protected by GFI. When I touched the center electrode of the grounded bulb to the chassis of the rotisserie, NOTHING happened. The 100 watt bulb did not light. No sparks. No tripped breaker. No smell of burning wire. With the bulb still in contact with the rotisserie, I measured the chassis at 28 millivolts (AC) relative to a non-GFI ground. The rotisserie continued to run normally and the heater element glowed throughout its length. In other words, I can't find anything wrong - except the 113 VAC when the bulb is not grounding the chassis. I know if I put a 3 conductor power cord on the rotisserie and plug it in to a kitchen (GFI) outlet, the outlet will trip. I am curious if a brand new rotisserie would exhibit the same characteristics.

 

Well, I finally got around to installing the so-called "new" heater element. As I expected, I measured about 113 VAC from chassis to ground when the rotisserie is running and the heater element is energized. I repeated the bulb test where I create a path through the bulb to see if the GFI trips. It tripped immediately. So, taking the advice I got from this forum, I repeated the bulb test using a power outlet NOT protected by GFI. When I touched the center electrode of the grounded bulb to the chassis of the rotisserie, NOTHING happened. The 100 watt bulb did not light. No sparks. No tripped breaker. No smell of burning wire. With the bulb still in contact with the rotisserie, I measured the chassis at 28 millivolts (AC) relative to a non-GFI ground. The rotisserie continued to run normally and the heater element glowed throughout its length. In other words, I can't find anything wrong - except the 113 VAC when the bulb is not grounding the chassis. I know if I put a 3 conductor power cord on the rotisserie and plug it in to a kitchen (GFI) outlet, the outlet will trip. I am curious if a brand new rotisserie would exhibit the same characteristics.

If it were me I just ground the chassis and call it good

Best regards
HP

 

If it were me I just ground the chassis and call it good

Best regards
HP

Well, I finally got around to installing the so-called "new" heater element. As I expected, I measured about 113 VAC from chassis to ground when the rotisserie is running and the heater element is energized. I repeated the bulb test where I create a path through the bulb to see if the GFI trips. It tripped immediately. So, taking the advice I got from this forum, I repeated the bulb test using a power outlet NOT protected by GFI. When I touched the center electrode of the grounded bulb to the chassis of the rotisserie, NOTHING happened. The 100 watt bulb did not light. No sparks. No tripped breaker. No smell of burning wire. With the bulb still in contact with the rotisserie, I measured the chassis at 28 millivolts (AC) relative to a non-GFI ground. The rotisserie continued to run normally and the heater element glowed throughout its length. In other words, I can't find anything wrong - except the 113 VAC when the bulb is not grounding the chassis. I know if I put a 3 conductor power cord on the rotisserie and plug it in to a kitchen (GFI) outlet, the outlet will trip. I am curious if a brand new rotisserie would exhibit the same characteristics.

Out of curiosity, I put the positive lead of my Fluke 87 meter in the AC milliamp port (can handle up to 400 ma) and took a direct current measurement between the chassis and a non-GFI ground. The meter read 0.0 ma before switching the appliance on. Turning the appliance on produced a reading of 1.8 ma which rose slowly to 2.1 ma. After a minute or two, the leakage current dropped back to exactly 2.0 ma. So, in conclusion, there appears to be 113 VAC floating on the chassis unless it is connected to ground through the light bulb. With the light bulb providing a path to ground, the voltage on the appliance falls almost to zero (28 mv). With the light bulb no longer connected, the leakage current between the appliance and ground is only 2 ma.

Conclusion: This type of appliance was not intended to be tied to earth ground. With the polarized plug, the GFI will trip if any current leakage is detected. I will be putting the rotisserie back into service as it is currently (pun) configured. I will monitor closely but I am convinced it is working normally. Thanks to everyone who provided feedback and ideas. Hopefully I can contribute some knowledge on future topics.

 

Out of curiosity, I put the positive lead of my Fluke 87 meter in the AC milliamp port (can handle up to 400 ma) and took a direct current measurement between the chassis and a non-GFI ground. The meter read 0.0 ma before switching the appliance on. Turning the appliance on produced a reading of 1.8 ma which rose slowly to 2.1 ma. After a minute or two, the leakage current dropped back to exactly 2.0 ma. So, in conclusion, there appears to be 113 VAC floating on the chassis unless it is connected to ground through the light bulb. With the light bulb providing a path to ground, the voltage on the appliance falls almost to zero (28 mv). With the light bulb no longer connected, the leakage current between the appliance and ground is only 2 ma.

Conclusion: This type of appliance was not intended to be tied to earth ground. With the polarized plug, the GFI will trip if any current leakage is detected. I will be putting the rotisserie back into service as it is currently (pun) configured. I will monitor closely but I am convinced it is working normally. Thanks to everyone who provided feedback and ideas. Hopefully I can contribute some knowledge on future topics.

Well... I guess you're gonna do what you're gonna do... IMNSHO a 2ma/60K_Ohm leak is unacceptable! The safest bet is to equip the unit with a grounded power cord and connect it to the 'mains' via a non-GFCI outlet...

Sincerely, stay safe!
HP

 

Have been following this thread, and just got curious and went to the kitchen to look. Don't have a rotisserie but have a toaster and toaster oven, neither have a polarized plug on them. So does that make them unsafe? Can't recall ever seeing a polarized plug on any radiant cooking devise.

 

I know I have gotten tagged on occasion by these non-polarized appliances, especially when using them heavily and making a mess as cooks sometimes do.

 

I know I have gotten tagged on occasion by these non-polarized appliances, especially when using them heavily and making a mess as cooks sometimes do.

My wife cooked dinner yesterday using the rotisserie for the first time since the repair. Everything worked as expected. It was plugged into a kitchen power outlet (GFI protected).
The rotisserie ran for a total of 45 minutes with the "new" heater element glowing cherry red. No issues, no shocks. Nothing tripped. No smoke. No arcs.
As a side note, I did make sure my wife's life insurance was paid up.

 

My wife cooked dinner yesterday using the rotisserie for the first time since the repair. Everything worked as expected. It was plugged into a kitchen power outlet (GFI protected).
The rotisserie ran for a total of 45 minutes with the "new" heater element glowing cherry red. No issues, no shocks. Nothing tripped. No smoke. No arcs.

While not wishing to play the gainsayer -- That's akin to declaring obedience of traffic regulations unnecessary on the basis that they may frequently be ignored with impunity [/parental_tone]

Best regards
HP

PS -- Re: the image: "Caution: Hot Surface" Yeah! No kidding!

 

Excelent, though I'm not sure they would pay for a death for unauthorized repair and use of a known defective appliance. It's a racket anyway.