Electrical Question - Kitchen Reno - Calgarypuck Forums - The Unofficial Calgary Flames Fan Community

PsYcNeT · 08-09-2016, 12:09 PM

Alright so I'm like 99% sure this isn't an issue at all, but I figured I'd tap the knowledge of some more experienced electrical bros.

As part of an upcoming kitchen reno, I'm planning to replace an exhaust hood which is currently powered by a pull of standard Romex w/ ground. The replacement microwave/exhaust requires a plug.

The existing Romex (I believe) junctions off a 120v/15a/60hz unused receptacle behind the stove (used if we changed to a gas stove, currently a 240v/30a electric with it's own dedicated line is there). Also on this circuit are a 9w LED exterior light and a 9w LED light in the pantry. Nothing else is on this circuit.

The microwave has a rated output of 950w (1500w max rating), and I would also like to also add plugged under-cabinet lighting which will in total pull ~22 watts of power. Altogether at max rating, the potential 1540 watt pull on this circuit is well below the 1800w limit on a 120v/15a circuit.

I don't see any issues with turning the Romex pull into a second receptacle in the cabinet above the stove, but I wanted to see if there was anything my admittedly amateur electrician brain was missing. Obvs introducing a gas stove at a later date could cause an issue (igniters on those use ~650w for a brief second) but only if the microwave was already running. Anything else I'm missing?

2Stonedbirds · 08-09-2016, 12:14 PM

Typically you do not want to load cicuits at or above 80% of the breakers rated limit. So around 12A you should be fine on that circuit. Renos are what they are anyways. If you are absolutely positive that those are all the additional loads then you should be fine. Most of them are intermittent loads anyways.

Watch when adding your new receptacle that wires are not close to edge of the stud. This will help your cabinet dudes out so they dont bury screws into your wire. *edit* nailing a flat piece of thin tin down over the stud where your wire passes through will also help ensure they dont blast it. Screw hits the tin but wont go any farther, cabinet dude grumbles, gives up, moves his screw another 1" and find a stud. Happy cabinet dude, happy PsYcNeT.

In a perfect world I'd pull a dedicated circuit for your new micro/range hood, but such are the joys of renos.

PaperBagger'14 · 08-09-2016, 12:18 PM

It will work but it will not be up to code. Code states that you must have a dedicated circuit for your microwave or microwave/hood fan combo. You may run into problems as you're running above 80% max breaker rating (12.83 amps). With that much current drawn, you may see nuisance trips over time but not immediately.

If it was me, I'd do my best to run a new circuit up to the kitchen cabinets (if possible, use your pantry as a place to open up a wall and fish a wire to the main floor).

PsYcNeT · 08-09-2016, 12:21 PM

Oh I'll be careful RE: stud placement to cabinet rails, because I'll be doing the cabinets too. Yes, I have a painful few months of crap coming up. I also have to take down a closet (woo wall removal) and rebuild an island from scratch (woo table saw time).

RE: Dedicated line, what's messed up is my (18 year old) houses' existing Microwave circuit is actually connected to 3 other receptacles, which have tripped the breaker a handful of times when running another appliance while the microwave was on.

2Stonedbirds · 08-09-2016, 12:23 PM

I'm guessing the basement ceiling is drywalled? Agreed with Paperbagger that a new dedicated circuit is the way to go. If you can this would be the ticket.

If you pull a new wire, pull in a 12/3. Gives you another hot conductor just in case. Chances are you never will need it, but if it's there it won't hurt.

PsYcNeT · 08-09-2016, 12:28 PM

I actually could pull a wire, I was just considering the lazy route because I'm lazy. Thankfully, my kitchen is situated literally above my electrical box, in a furnace room that does not have a ceiling.

Yeah I'll pull a new wire and pull out that Romex circuit. Bah. Thanks for the advice guys.

EDIT: So would I have to create a second receptacle (assumedly on the original circuit) to plug the under cabinet lighting into? That seems wasteful :/

2Stonedbirds · 08-09-2016, 12:34 PM

You're laughing then! As an aside, is your fridge on a dedicated circuit? If not and if you can get to it what I would do is tug in your new 12/3 to your micro/hood, then pull a 12/2 over to your fridge. Dedicated circuits for everyone! (Oprah face) No chance of spoiling food due to nuisance tripping.

2Stonedbirds · 08-09-2016, 12:35 PM

I'd leave the first circuit that you are planning on pulling out and using it for your U/C lights. You'll be well under a 80% load rating for a 15A cct there.

Errr misunderstood your last question. Is your U/C light receptacle going into your cabinets, behind plates ect? If it was me what I would do is cut the transformer off the end of the U/C lights cord end, put it whoever you want so it's out of the way and pull low voltage cable from it thru whatever walls ect up to your U/C lights. This way you can easily hide the low voltage cable under the cabinet trim with sticky backs and zip ties. Fighting with #14 cord and a transX can be a pain in the willy and if it's all hidden your significant other will be proud of your handy work.

PsYcNeT · 08-09-2016, 12:42 PM

Yeah the fridge & oven are both on dedicated lines, the lights, dishwasher and 2 receptecles on the wall share a line, there are 2 GFCI plugs on/in the island (garburator), and then the Microwave receptacle + 3 other receptacles share a circuit, then there is the one I described in my original post. Lots of dedicated circuits in this house.

2Stonedbirds · 08-09-2016, 01:10 PM

You're golden Pony Boy.

I would still run a 12/3 to your hood, like I say if you ever need to add anything you'll have a extra hot and in the very unlikely event you do another reno and need to add another counter rec you have a #12 wire there to move.

Good luck.

PsYcNeT · 08-09-2016, 01:15 PM

So here's a theoretical:

I have a Kill-A-Watt. If I run a test on the highest settings for the microwave and come up with a max wattage hit below 1400w (so, below the 80% load on a 15a line), can I fudge it? Still trying to be lazy.

2Stonedbirds · 08-09-2016, 01:25 PM

That's really your call. That's why I said before that 'renos are what they are' because there's a perfect world scenario and then there is renos. I would strongly recommend a new line, especially if it's half easy to make happen ie you don't have to pull down basement ceiling drywall or the like.

Nothing is gonna piss you off more than nuisance tripping though when you have a brand new finished kitchen. I've seen some panels/breakers that you can weld with like old federals, and then some that are very temperamental.

Again I would if at all possible run a new line, but a couple extra low watt loads that don't have inrush current like a LED light isn't going to be a killer.

Whatever you do please do not upsize breakers on existing CCTs. CP would be sadly low on smart alek comments if you burn to death in the middle of the night.

speede5 · 08-09-2016, 01:38 PM

Quote:

Originally Posted by PsYcNeT

So here's a theoretical:

I have a Kill-A-Watt. If I run a test on the highest settings for the microwave and come up with a max wattage hit below 1400w (so, below the 80% load on a 15a line), can I fudge it? Still trying to be lazy.

Simple answer - no. As soon as you alter the cct you have to bring it up to code.

Kitchens have a lot of factors to consider and there are lots of rules to follow, all for good reason. Go to your building store and buy the P.S. Knight simplified electrical book. It is updated routinely with the new codes and is a great guide for renovators. The code did just change, and I've heard there are a lot of tweaks.

And if you use 12 as 2Stonedbirds suggests go all the way with 20A breakers and outlets. Electrical ccts are only as strong as the weakest link.

Remember you should still be pulling a home owners permit and doing everyhing to code.

PsYcNeT · 08-09-2016, 02:17 PM

So after this excellent advice here, I'm likely going to just use the electrician I was going to have move the GFCI receptacles do this one as well; it's just going to mess up my project timelines a bit, as I won't be able to hang that cabinet(s) until the socket it in. C'est la vie.

Better not to screw it up, it's a bit more than just replacing switches or light fixtures. I don't really feel like opening up the entire wall for inspection purposes either if I can avoid it, though an electrician may have to anyway.

PaperBagger'14 · 08-09-2016, 03:24 PM

If you're having an electrician do it and run new wire, id ask him to also do above cabinet lighting and to have them all out on another switch in the kitchen or somewhere appropriate.

PsYcNeT · 08-09-2016, 03:29 PM

Quote:

Originally Posted by PaperBagger'14

If you're having an electrician do it and run new wire, id ask him to also do above cabinet lighting and to have them all out on another switch in the kitchen or somewhere appropriate.

The cabinet lights use a wireless remote switch that mounts whereever, so that's not much of an issue. I also realized that I can choose to buy a plug-in version or a direct wire version of the transformer, so I'll just get the direct wire version and wire it into the old vent hood Romex to keep if off the microwave circuit.

Wiring it up into the cabinets will be no problem; I've put in a lot of cabinet/shelf lighting in my time.

OMG!WTF! · 08-09-2016, 03:30 PM

You might also have to relay your new hoodfan to the furnace if sucks more than 300 cfm. Not sure about that but worth looking into.

PsYcNeT · 08-09-2016, 03:33 PM

Quote:

Originally Posted by OMG!WTF!

You might also have to relay your new hoodfan to the furnace if sucks more than 300 cfm. Not sure about that but worth looking into.

Even if it's already venting outside? There is a separate vent already running through the wall.

EDIT: It's 400cfm. BAH.

OMG!WTF! · 08-09-2016, 03:37 PM

Quote:

Originally Posted by PsYcNeT

Even if it's already venting outside? There is a separate vent already running through the wall.

Oh yeah because it's sucking air out of the room so you need to bring air back into the room or your eyeballs will dry up. Kind of a crazy code but some of these industrial fans hit 1000 cfm. And houses are so sealed up these days I guess it could be a problem. Check the cfm rating on yours.

woob · 08-09-2016, 03:41 PM

I did a kitchen reno a couple years back, and had the same ease of access to the panel, as it was right below the kitchen.

1. Take out the drywall from above counter plugs down.
2. Wire to your content, adding in more circuits/plugs than you think you'll need.
3. Drywall back up and tape/mud.
4. Put your cabinets in.

I tried to figure out how I could cut corners here and make things work there, but in the end going the route I did was the best choice and was not that bad, work wise. Being that the drywall is behind cabinets/backsplash, there wasn't a lot of sanding required (unless you're an awful mudder).

End result is I had enough 20amp circuits, had ample plugs, and I passed inspection first time.