Kitchen Renovation Science for Dummies

[Chris Amirault]

As noted in another eG Forums topic, I'm renovating and updating a 1950s kitchen. While there are a number of projects I can handle involving screws, duct tape, and the like, I'm facing my fear of electricity and other kitchen sciences with two big projects: an overhead four-bulb fluorescent lighting fixture and -- the biggie -- replacing the vintage Thermidor ovens. The current contender for replacement is this Cadco oven, and I am overtaken by awe and fear every time I look, longingly, at the thing.

I know, I know: it's pathetic. I'm turning to you for help.

My questions run the gamut. Right now I'm running all my appliances and gadgets through two-prong outlets with adaptors: what risks does that pose? What the heck do these things mean?!?

• Oven cavity wrapped in high ”R” value insulation
  ...
  
• NSF, UL (through CSA Standards)
  
• 208-240 volts 5600 watts 24.4 amps Single Phase /NEMA L6-30 Plug

Are there any reliable resources out there on electrical know-how for kitchen renovation? What sorts of basic information on electrical systems should someone know to tackle home improvement projects like this?

[Chris Hennes]

The high "R" insulation is just telling you it's got good insulation (well, sorta, that's what the marketing people are trying to say, at any rate). UL is the Underwriter's Lab, they test stuff to make sure it is safe. And the voltage and amperage means you need a 220 volt household circuit, which is twice what a normal wall outlet delivers (in the US). Your old oven probably already had that, but you'll know immediately based on the shape of the plug. A NEMA plug is three-pronged, and the prongs are arranged in a circular formation: it's very different from a standard household outlet, you can't miss it. When I need help with this stuff, I usually go to the Samurai Appliance Repair Man. He's more than a little opinionated, but he's got lots of good info.

[Chris Amirault]

In this context, what does the wattage mean? Feel free to explain it in other contexts as well, btw.

[Chris Hennes]

Watts are a measure of power: mathematically, it's the current times the voltage. It tells you something (but not everything!) about how quickly the oven will heat up, how hot it can get, etc.

[ChickenStu]

It tells you something (but not everything!) about how quickly the oven will heat up, how hot it can get, etc.

More so how much power is consumed rather than efficiency.

[qrn]

for the amount of $ the oven you are looking at is you probably can get a Thermador microwave/convection/normal oven combo.. I have one and its great..Not sure of the vintage of your thermador ovens but the real old ones had an exhaust stack on them so when you roasted a duck the smoke went outside,,,none of the new ovens have that any more...

Bud

[budrichard]

Before proceeding further, contact your local Building Inspector, and ascertain the local Codes, whether or not you require Certification to do the work you are contemplating. You may have to take an exam to obtain Certification. Your Fire Insurance may not be valid if the work is not done to Code by a Certified installer and you may be at risk from incorrect installation.

As a Power Plant Engineer, I leave electrical installation to an IBEW installer and insure the work is done to Code.-Dick

[LindaK]

I know, I know: it's pathetic. I'm turning to you for help.

Chris, it isn't pathetic. Fear of badly done electrical work is a sign of good mental health. Electricians aren't cheap but I'd consider it money well spent. I will aways remember the look on my GC's face when he showed me the dangerous amateur wiring job lurking behind my kitchen walls after they were demo'd for the renovation. Changing a light fixture is one thing but I'd consider consulting an electrician for any appliance upgrade. Plus, as others have noted, building code requirements in your city may also have something to say. If I'd wanted to put a new range or oven in my pre-existing kitchen, I couldn't have done it within code without various upgrades.

To your question, it's not hard to find the electrical/plumbing specifications for any new appliance. Search the web for its installation manual. It will tell you what the appliance requires, from the necessary voltage and gas line size to specific location requirements for electrical or plumbing connections. The instructions for my range, for example, not only required that it have its own dedicated electrical line but also specified the exact location of the electrical outlet and the gas line. New appliances are finicky.

Have you already discovered the Home Forums on Garden Web? That site not only has specific subforums dedicated to kitchens but also electrical wiring and appliances. It's a black hole, but still can be very useful: http://ths.gardenweb.com/forums/

[lesliec]

Chris, if I remember from your earlier postings on your new/old kitchen, the existing ovens are built-in. The manual for the Cadco says, in large friendly letters, Your oven is not designed for built-in applications or for side by side positioning. They even underline it, so it must be important!

Apologies if I'm wrong about the old ovens and/or teaching you to suck eggs, but the language if you bought one and then found you couldn't put it where you intended doesn't bear thinking about in a family forum like this one.

[andiesenji]

The Cadco works in the space but not like a regular "built-in" oven.

I have friends who had the same double Thermador ovens in their Eichler home and did not wish to do a major reno that would change the character of the original classic mid-century design. (This was also a "Gold Medallion" all-electric home which touted the "Live Better Electrically" theme. Some of the countertops had to be replaced but they were able to find the vintage Formica that matched and also a Formica and chrome dining set in near-mint condition. Their house was featured in a Sunset magazine article twenty-some years ago when mid-century modern regained some of its popularity.

Now Eichler homes, even in disrepair, are snapped up as soon as they are on the market, in spite of the bad real estate market.)

They had the cavity that existed to house the double ovens boxed in and completely tiled, except for the existing vent that was fitted with a small, integral exhaust fan (fitted into the vent pipe).

In this tiled space the Cadco oven has sufficient clearance on all sides to comply with its working efficiently and safely. There was enough free space at one end to allow for a storage area for sheet pans, etc.

They did have an electrician check the breaker box and the existing wiring as well as install some additional outlets on a new line to serve additional appliances.

There is also a strip of halogen lights along the top front edge of the space which really spotlights the oven. It certainly impressed me!

I've had the half-size Cadco oven for years and I love it. If I needed the bigger one, I wouldn't hesitate to buy it.

Edited July 27, 2010 by andiesenji (log)

[IndyRob]

I just got all new appliances for a house. The installers were able to do all the wiring for not very much extra. Normally I'm willing to do 110 volt wiring myself, but won't touch 220.

Also, if you need to change any plumbing check out Sharkbite adapters (at Lowes they're called Gatorbite). I was dealing with a little plumbing issue and as I wandered the plumbing isle at Lowes trying to fit together different pieces the plumbing guy there suggested these. When he explained how to use them, I was dumbfounded. It's snap-together plumbing. It works with copper, PEX, CPVC (two kinds of plastic pipe) and can be used to transition to/from any of these. To use, push it onto the pipe. That's it. There's a cheap little tool you need to remove it and reuse it if you make a mistake (which I did). I don't know about local codes, but supposedly it's approved for use inside closed walls.

[Chris Amirault]

Just to be clear, I am trying to learn me some electricity so that I can be a knowledgeable consumer of estimates, jobs, and products. I have no intention of doing this electrical work!

I have a pal who's smart about these sorts of things, and he wrote on my Facebook page:

A "High R Value" is totally subjective and without a number is kind of irrelevant. Ultimately the higher the R value the more efficient the oven should be...

CSA is the european equivalent of UL. Its a 3rd party agency that ensures that electrical products meet safety standards.

208 volt is what you would see in a commercial US kitchen, 230 would be standard in Europe, and 240 is what you would be using in your house, which is 2 legs of 120 volts, just like a dryer or hot water heater.

An L6-30 is a standard commercial high voltage twist-lock plug. The L means it is a twist lock, the 6 indicates high voltage (up to 250v) and the 30 means 30 amps.

Volts * Amps = Watts

For this oven you would want a dedicated 30amp circuit. If it uses an L6-30 it is looking for a 3 wire connection - 2 hots, and a ground. There is no neutral is this type of setup. I'm not entirely sure if it meets code for a house, but its very standard in a commercial kitchen.

Also - the lack of a ground on the other stuff - Rightfully you should have a ground on all your outlets, but obviously rewiring the whole house is a big proposition. To get rid of the adapters in the short term - you can just replace your 2 prong outlets with new 3 prong outlets. They cost next to nothing and it takes maybe 5 mins per outlet to do.

Realistically the biggest problem with no ground is that a surge protector cannot function - beyond that most any other piece of equipment is fine. One thing I would recommend is that if you have any outlet near a sink to replace it with a GFCI. They cost maybe $10, but will keep you safe in the event your wife tries to kill you by throwing a vintage toaster into the sink while you are doing dishes.

That last part is not a reflection on marital harmony at Casa Amirault. Ahem.

[DanM]

I am not an electrician, but my family owned a hardware store for 83 years... here is what I learned from my time there.

...an overhead four-bulb fluorescent lighting fixture

Is this light flush with the ceiling, or is it mounted to it? A flush mounted light may be a bit of work due to the drywall work needed to fill the hole.

Right now I'm running all my appliances and gadgets through two-prong outlets with adaptors: what risks does that pose? What the heck do these things mean?!?

A modern three prong outlet has a grounding post to help prevent you from getting shocked in case of a fault in the appliance or if you accidently spill liquid over it. Three pronged outlets also have a larger slot on the left for appliances with a polarized plug. Ideally, you will want to replace these outlets with GFCI outlets for the most protection. Most municipalities require them. Replacing an outlet is not rocket science, but it is best to have someone who has done it before help you out.

Here is more detail on this.

http://electronics.howstuffworks.com/question110.htm

Regarding your friend's comments on Facebook. Given that your house was built in the mid 50's on the East coast, I will bet a beer or two that your electrical is based on flexible metal conduit with rubber coated, cloth covered wires. The outlet grounds to the conduit via the standard metal electrical box. The conduit then grounds back to the circuit panel, and then to ground or the water pipe coming into your house.

Edited July 28, 2010 by DanM (log)

[Chris Amirault]

Thanks, DanM.

Is this light flush with the ceiling, or is it mounted to it?

Mounted to it in a big, ugly box with wires sticking out. Gotta remove that whole thing and stick something else up there.

I'll be in touch about that beer....

[RobertCollins]

Chris, your friend steered you dead right but for one little mistake a commercial electrician might miss. You can only replace a two prong outlet with a three prong IF it is a GFCI circuit. This is true any where in the home and has been in the National electric cod since the 90's.

All the outlets down stream of a GFCI are protected by it if the wiring is parallel so they may be just standard three prong outlets, your friend will understand this. All kitchen outlets should be GFCIed so the few bucks will help keep your family in better stead.

Don't know if a locking plug for an oven would be required here so I would check your local code. I would just hard wire it, I can't see a home oven need to be cord and cap connected. In a restaurant where appliances need to be moved often for cleaning, make sense though.

I'm a half assed cook but I do hold a Master Electrician license in Washington State and a Journeyman IBEW Card since 1972.

I do like that kitchen.

[MSRadell]

Chris, your friend steered you dead right but for one little mistake a commercial electrician might miss. You can only replace a two prong outlet with a three prong IF it is a GFCI circuit. This is true any where in the home and has been in the National electric cod since the 90's.

That's not true if there is a ground available in the box except for certain locations. As long as a separate grounds conductor is available you can install a normal 3 prong receptacle in bedrooms, living rooms etc. GFCI's would definitely be required any place in the kitchen but not necessarily in some other places. That's one of the reasons to consult an electrician familiar with your local codes.

[RobertCollins]

I hadn't considered that a 1958 house might have a ground wire nor did I remember that many places in the east required conduited systems in which case, they have a ground system. A cabled system of that era might also have an armored cable system [bx] and that would likely have one of those 16 or 18 reduced size grounds. I have nearly zero experience with the old loom cable systems but I think they quit installing them around the end of the forties. I don't know if they had a grounding conductor or not.

In any of these cases a properly installed 3 prong outlet would be acceptable but the kitchen should still be GFCI.

Chris have your buddy get you a xerox of National Electric Code article 210.8, It will provide the knowledge of what to expect you will need when the electricians give you a proposal.

Thanks MSRandell, good catch.