I recently had a call to check a "food warming table" because the GFCI recpt. would trip when 2 elements(there are 4 elements total) were turned on. This is the type of table that only has elements in the bottom to keep the food warm and containers are set in over the elements. I looked at the nameplate and it pulls 2000 watts (16.7 amps). It was on a 20 amp breaker. I figured since it was pulling a little over the 80% requirement of the circuit that it needed a 30 amp. circuit so I installed a 30 amp. circuit and put it on a 30 amp. single pole breaker, still on a 20 amp. GFCI receptacle. It could now hold for 3 elements then would still trip out. I checked the elements to make sure one was not bad or the wiring was bad or wired wrong and found nothing.
I then thought the 20 amp. GFI might be maxing out for the 80% amperage. I got a 30 amp. GFI breaker and installed it. It still would hold for 3 elements but would trip when the 4th one was turned on. I called a kitchen equipment supplier and talked to them and they said their electrician took theirs off a GFCI and put it on a regular breaker. I had to do the same but am concerned why this would happen. Looks like it should be on a GFCI. It is located in a brand new Picnic shelter that was inspected. Where is sets is a kitchen like divider with counter space with no sink but on a cement floor. The receptacles around the counter are GFCI protected. Any ideas? Thanks