I put a GFCI in the first kitchen receptacle and it went in fine because there are enough connectors on the GFCI to connect both outgoing wires without having to pigtail everything. All was fine until I turned on the overhead kitchen light, which tripped the GFCI. The second receptacle also houses the light switch over the sink, (not the same light that tripped it), and who knows what else. The only way to get the GFCI not to trip when the kitchen light is on is to wire the other receptacle feed to the line circuit, instead of the load, which means that I have to put a second GFCI in the other receptacle. I don’t have a clue why the kitchen light was tripping the GFCI but the sink light doesn’t, only thing different is that the kitchen light is a 3way. So then I go into the bathroom and see that the lights are out when the GFCI in the kitchen is tripped. I put a 15A GFCI in the kitchen because it was $10 cheaper than the 20A, but now that I’m seeing there is a lot of things on this one circuit and that I should put in a 20A instead. At least there is no need to put a GFCI in the associated bathroom. Anyone have a clue why the kitchen light would trip a GFCI?

Andyman, don't worry about changing that 15 amp GFCI to a 20. The feed-through rating is exactly the same on both. (Look on the box or the receptacle. Both will tell you the same thing about a 20 amp feed-through rating.)

Sounds like you are due for another GFCI. Either that or figure out why that light has a cross-connect between ground and neutral. (That is the most likely cause but there might be a different one.) A ground to neutral connection isn't the easiest thing to test since they will always be connected back at the panel. I think I'd temporarily undo the ground wire for that particular circuit back at the panel for a test. Once you do that there should be an infinite (near infiinite) reading on an ohm-meter between white and bare. If not, chase down where they are cross-connected. Make sure you reconnect that safety ground at the panel.

As far as how replacing the panel would be accomplished, a very simple explanation would be:

The electrician would identify the circuits and shut off the power to the whole box. The wires would be slipped out of the knockouts they enter - usually it's NM wire (Romex) with clamps that slip into the holes and are held in place with a locknut. The whole box would be removed. A new box would be mounted to or in the wall (most likely in) and the appropriate knockouts punched out and the wire clamps and then the wires would be put back into the holes (knockouts). The hot wires would be connected to new, appropriate breakers (a good electrician should attempt to balance the load if it isn't already), the neutrals to the neutral bar, the grounds to the equipment grounding terminal. Then after checking, they should turn all the breakers off, turn the power back on to the whole box, and turn the breakers back on one at a time, checking the circuits as they go.

An electrician may very well pigtail some of the wires to make them reach the new breakers (and this is allowed by the current NEC code book as far as I know).

What I've written is not really instructions, just sort of an example. Basically, a good electrician can replace the breaker box and will know what to do if problems occur (and there can be none or a whole bunch when replacing a whole panel). Always have an electrician do this (don't do it yourself). Also, an electrician should be able to figure out before starting if there are problems like no ground wires, wires too small, etc. (Current code requires ground wires and 12 gauge wiring for "branch circuits").

As far as the dishwasher box, it probably would have been better to put a junction box further away and run either waterproof conduit to the receptacle, or run waterproof cabling to the receptacle. Then you could have just added however much wire you needed from the other side of the junction box to the receptacle. I'm not sure if a junction box in a crawlspace would have been best either if its that hard to get into (there are rules about where you can and can't put a junction box), although you might have been able to fish the wire into a wall further away and put a junction box there (but then it would be in a room - junction boxes are supposed to be "accessible"). There are actually waterproof junction boxes and fittings as well. If a new panel is decided upon, just have the electrician look at the dishwasher stuff too - its a lot cheaper for them to do the work at the same time than to have two separate calls.

By the way, if an inspector is ever called to the property they probably will complain about the FPE panel. I don't know about your area but mine requires inspection before an apartment is allowed to be rented to someone.

Always check with somebody else too, as I'm not an electrician (I'm just interested in electrical).