Oven Electrical Question

I am replacing my built in oven/microwave combo with a separate thermal oven and a microwave. The oven will take 220 V, the Microwave is a plug-in (built-in) above the oven and requires 110V.
Can I extract 110 V for the MW from the 220 V junction box (line to 220V thermal oven )? The 220 V line has a 40 Amp Circuit- breaker.
This house is 25 years old. I cannot tell if 3 or 4 wires go from the main panel to the junction box.
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Walter
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No, you'll need to run a dedicated circuit for the microwave

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or possible fatal shock, CALL A LICENSED ELECTRICIAN!
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25 years old is probably 3 wire. That makes the idea impossible, even if you were willing to put in a load center.
It would be a bad idea in any event.

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Possibly...
.. but you need to find that out first. With 3 wires, it's impossible to do it safely and legally (you need, but don't have, a neutral). With 4 wires, it's merely impractical.
Here's the problem you run into with four wires: the microwave almost certainly is intended to plug into a 15A (or maybe 20A) 120V circuit, but your existing wiring is likely 8-gauge. 120V receptacles aren't rated for wires that large, and cannot grip them securely, so you'll have to have 12- or 14-gauge wires going to the receptacle for the microwave -- but it's a Code violation to put anything smaller than 8-ga on the 40A circuit that you now have.
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Regards,
Doug Miller (alphageek at milmac dot com)
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OK. Thanks. Back to the drawing board.
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Walter
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