researching-elec questions

[willy535]

hi,been lurking for a while and ready to build.structually i have no problems.understanding wiring is another thing.i plan on building using 4-2500w elements.few 's
1)when wiring element,do you have to use connectors like on an oven,they seem to be ceramic type insulators.or just use connnectors.
2)i see alot of people use the standard 40amp contactor,like 4dd09 from mcmaster.will this suit me.i think i need 45amp but this one has 50 amp resistance and i see many use it.
3)what could i use for on/off switch.i will have main shut off for both legs,but at control box the on/off switch will be on one leg.what do most guys use. thanks in advance.......william

[hbracing]

There are a lot of nice ovens in this forum and they all I am sure do a fine job. I do think some of the guys go a little crazy with their electronics and controls. The same job can be done with far less expence, but thats up to the individual. You can use a multi purpose contactor from your local appliance repair shop or Grainger. If you know an HVAC guy he can get everything you need from the HVAC or Appliance wholesale house for cheaper than you might expect. Keep in mind that these controls need to be located from the heat but thats no big deal. I am going to use a thermostate out of the oven that I am taking the elements out of. I do have a background in HVAC and appliance repair so this is no problem. Be safe and choose yor parts to handle the amperage you need. Apply OHM'S Law and add 10-20% will be a good starting point..............

[gourdhedd]

Originally Posted by willy535

1)when wiring element,do you have to use connectors like on an oven,they seem to be ceramic type insulators.or just use connnectors.
2)i see alot of people use the standard 40amp contactor,like 4dd09 from mcmaster.will this suit me.i think i need 45amp but this one has 50 amp resistance and i see many use it.
3)what could i use for on/off switch.i will have main shut off for both legs,but at control box the on/off switch will be on one leg.what do most guys use. thanks in advance.......william

1. My experience with oven elements is that they have a screw connector on each leg which you wrap your incoming wire around and tighten. A few have some sort of proprietary plug-in connector which can be mounted to the frame of the oven, the wires of which are connected to your incoming wires with wire nuts, if nothing else.

2. Don't know about your McMaster contactor, but most contactors are given two ratings, FLA and resistive. The FLA (full load ampere) rating is for controlling motors which will , in fact, draw a much higher current while coming up to speed, or when loaded and their RPM is reduced by the load momentarily. Resistance elements, on the other hand, don't have the high starting or loaded current draw, and the so the rating is a bit less conservative. 50amps of resistance elements will only draw about 50 amps or a little less. A typical contactor may have a 40amp FLA rating and a 50amp resistive rating.

3.The ON/OFF switch should be wired in series with the thermostat and controls power to the contator coil only. The contactor coil has very minimal current requirements so the ON/OFF could be a light switch for a house (the cheapest) or a toggle switch.

[mtumbleson]

[quote] 1)when wiring element,do you have to use connectors like on an oven,they seem to be ceramic type insulators.or just use connnectors." [quote]


I just found them on McMaster-Carr, page numbers 722, 720, 725, 729.
Or, just do a search for wire connectors then move to the high temp. connectors.

Don't forget that you will need high temp wiring, McMaster has that too, page 764 or search for wire then move to hi-temp from there.