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Element requirements?

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  • Element requirements?

    Hello, I've been doing a lot of reading on other oven builds and noticed quite a difference regarding how many elements are being used for basically the same size oven. I was wondering how to calculate the requirements for my oven. It's roughly 32"x32"x5' interior dimensions, the walls are galv sheet with metal 2x4 framing and rockwool insulation.

    Also I've been scoping out PID's on e-bay and notice a huge difference in price for what appear to be the same units. I know the old adage "you get what you pay for" but I'm building this thing on a very tight budget and it is for hobby use only (PC'ing motorcycle parts for me & my friends).

    I'm no electrical genius, I can read and understand wiring diagrams but am lost when it comes to watts/amps requirements.

    I'm figuring I need to know how many of what watt elements I'll require first off and that will dictate what (or how many) SSR's I'll require. I've searched and can't find a calculator that will outline requirements based on oven dimensions. I read the BTU calc thread and that just flew over my head I guess?

    Anyone have any suggestions?

  • #2
    Re: Element requirements?

    5-6k watts (2 typical oven elements) will do just fine. That will put you at around 20-22 amps so a 30 amp 3 wire with ground circuit will be required. Only one ssr or contactor would be required, just find one rated 30A or above.

    I don't recommend any of the cheap pid's so you're on your own there. If you can find a reasonably priced Watlow model 93 or SD31 used you won't be disappointed.


    • #3
      Re: Element requirements?

      Just out of curiosity, how do you figure that out? Not that I'm doubting you in the least. I just like to learn/understand. Is there some equation that can be applied?


      • #4
        Re: Element requirements?

        I've been involved in this forum for several years so a lot of it is just experience and a fair memory. There is a good calculator (Excel based) that is referenced in the sticky on the top of this forum(BTU Calculator). IMO the Excel calculator does a better job estimating oven requirements than the other link that is designed for calculating house insulation needs.

        Your oven size is almost the same exact size as the oven I've built and have been using for the last 7 or 8 years so I also have some first hand experience there.
        Last edited by ed_denu; 05-12-2014, 11:25 PM.