Crimping Electrical Joints in Cooking Appliances

If you have access from the side:

You need to solder in a polymeric positive temperature coefficient device (PPTC, commonly known as a resettable fuse, polyfuse or polyswitch) ....

http://en.wikipedia.org/wiki/Resettable_fuse

I don't know about using these for fire safety, especially if they are not what was installed when the unit had a OEM UL review.

These poly fuses have a bad habit of letting you know that they have a lot of undocumented characteristics when you slowly and gently overload them. The trouble we had with them and trouble getting better documentation made us walk away from them (at least for now).

Hydraulic crimper

You can find a inexpensive one for about $60.00 US.

I use one to crimp ss ring terminals to the ss leads on IR lamps used in an oven. You do need to be careful as to not to over crimp. As they will distort the wire badly. You don't want to reduce the wire size too much.

...or buy two brand new hot plates, $30.00 ea.

He said the space is very reduced to fit a crimping tool. That's why I suggest the "ahorcador"™, that way he can slip both conductors in, overlapping, and tighten the screw.

For solid to stranded wire, wire nuts: End view showing metal inserts

Lyn, Absolutely not! Plastic wire nuts are usually rated for a maximum of 90ºC, a temperature which is routinely exceeded in a hot plate, waffle maker, etc., and may lead to rapid failure of the plastic shell, though I have seen old ones with a porcelain shell.

Better to use an uninsulated seamless barrel/butt crimp and an ordinary indent style crimper.

Ceramic wire nuts are the answer; 42 is not.

There's a great dearth of information about the current carrying capablility of joints made with these things - all the suppliers seem to quote is wire sizes and voltage and temperature ratings.

Never the less, they are ubiquitous in home wiring.

Haven't personally seen then used other than for lighting and light duty (e.g. ceiling & extractor fan) wiring.

Have seen them used, and I use them, in many applications just like the submitted problem with heat. They are still in use and are the best thing for higher temp applications. Every time the wife busts the toaster I go to my supply and get some for that use. Stock them since she is very adapt at busting toasters! Unfortunately, the daughter has been taught by her mother on how to bust toasters!

Good Luck, Old Salt

You obviously have not been in many houses to examine the wiring.

There are millions of them in use all over the USA.

It is a standard connection in house wiring,and they are rated by the number and sizes

of conductors allowed,and the temperature range.

Some are rated for solid wire only,some for combination stranded and

solid conductors.

Some have wings (for extra torque) and some don't .

There are even special ones for joining aluminum and copper wires together.

These are expensive,and used to be color coded green,with wings.

But, they may have changed colors or configuration since I retired.

Yes,the very small ones are used in ceiling fans and lamp ballasts or tubes,but they

are also listed for such use because of the higher voltage from ballasts and the

higher ambient temperatures in signs,such as neon or billboards.

Not here!

How do you make connections from an overhead junction box to a wall switch or to

perhaps a light,or switched receptacle,etc. in your country?

What is used for connecting wires in residential occupancies in your location?

My mind is always open for new and better methods.

e.g.

http://www.screwfix.com/c/electrical-lighting/junction-connector-boxes/cat7230012

Spot welding is very common. it's done with a capacitance welder. I've done that too.

Where I worked we used a modified version of the method in post #1 in a vacuum system. However, 2 screws, one at each end is better,

Stainless tubing works OK.= drilled and tapped, Fiberglass sleeving should be available for your application.

If you have room ceramic terminal blocks are available, but they are usually big.

Google for:STRATO-THERM High Temperature Connectors ,made by AMP.

As a matter of fact,this was so easy,here is a link, to save you from all the work of researching it for yourself:

http://datasheet.octopart.com/50840-Tyco-Electronics-datasheet-595980.pdf

You're welcome

Can't go wrong with soldering the wires together. If you need to lengthen them, because of space, be sure to use silicon -insulated wire, and not PVC.

Depends on type of solder.

Silver solder,or Sil-phos,ok; tin/lead solder,not good.

This type solder will deteriorate under even moderate temperature extremes over time, creating a bad joint.

Solder joints are illegal for house wiring in the USA.

Solder joints are illegal for house wiring in the USA.

Really? NEC 110.14B clearly allows soldering (paraphrased - if you know what you are doing) and I don't see where it says that Article 110 applies only to industrial use.

Technically,you are right,but I have done contracting work in 17 states,and I have

seen only one AHJ approve of soldered connections on house wiring,and it was an old

existing work,in Louisiana.

IF(and that is a big IF) the joint is mechanically tight and secure,and the wires are

properly cleaned,and properly soldered,the joint will give good results,but I have

seen solder joints on old equipment turn cloudy,and crystallize with age.

And not just in old vacuum tube radios and TV's,but on automotive relays and

industrial relays of modern recent vintage.

There is also the newly discovered "tin whiskers" that result from solder over

time,weakening the solder and causing short circuits on PCB's.

Tin whiskers are blamed for the run-away-Toyotas a few years ago.

Not a problem in house wiring, there is nothing to short to,but the whiskers have

been shown to penetrate the multi-layer conformal

coating on PCB's,so it is possible if two conductors are in close proximity a

breakdown of the insulation could occur,resulting in a spark as the whisker vaporized.

The problem the AHJ's had was it is nearly impossible to properly inspect a solder

joint.

And they are easy to do improperly,but just about anyone can install a wire nut,

and checking it is no problem.

The problem I would have is the time consumed,not just in soldering, but in properly

insulating the joint.

If anyone wants soldered connections in his house,he will pay a very high additional

charge.

I haven't done domestic wiring in over 20 years,(not enough profit) so

industrial\commercial has been my field since around 1987,and I am now retired.

Now,as for the coffee pot or hot plate,a copper crimp is actually a better conductor

than the stainless that the factory uses,but they chose SS for mechanical strength.

And the OP did ask for a hi-temp connector,to which I did direct him.

A Teflon or fiberglass sleeve over the splice will suffice.

Sorry for the delay - I was out of town and way off the net.

I suspect this is similar to the switched neutral debate, where every electrician is taught that doing so is illegal, but section 240 allows it with definite conditions. If it is likely to cause a problem, just tell all that it is not legal and bad situations are eliminated.

I never wire in houses, just industrial work, but I might actually consider it for my own house, as I have never really been a fan of wire nuts. I've seen too many green wires inside them, and have been soldering at a professional level for 40+ years. Besides, the mess that the professional plumber left me, who tried to wire my house when he lived here, is far worse than any solder joint would ever be. I am actually surprised there are no solder joints in the wiring here. The plumbing is magnificent. I have 3" soldered copper tube sewer pipe. I have no intention to wire the house of someone else, so it will never become an issue here.

I have successfully used a Crimp-Sleeve wrap-cap by Ideal for industrial purposes,

and IF the proper crimp tool is used,they are super-reliable.

More expensive than twist locks,but faster than solder joints,and from personal

experience,more reliable than even solder joints, over extended time intervals.

I once saw a 3phase 600 volt motor still running,totally submerged in water without shorting out of the wiring.(A condensate return pump in a pit).

When the water drained out, I wanted to see what type connector was used in the motor junction box.

Junction box was full of water.

It was the crimp-sleeve wrap cap.

Connections were still dry when I removed the wrap cap.

I cannot recommend these for submergence duty,but I know they can take a lot of abuse that they are not rated for.

They are easy to examine without breaking the circuit,if necessary,

(as in a stop-circuit),

and if the crimp needs to be replaced,to modify the circuit,the wrap cap is reusable.

Here is a http://www.cesco.com/b2c/product/Ideal-30-417-Wrap-Cap-417-Insulator/19549

At $73.25 a hit, they should be good!

NOT $73.25 EACH.

That is the price PER BOX.There used to be 100 per box,but that page does not state quantity.

The crimp sleeves and wrap caps are sometimes sold separately,sometimes as a set.

Shop around on Google for best price.

Fortunately, all the wiring we do here for process skids are in NEMA 4 junction boxes, so water is not an issue for that use. We use the standard wire nut with rubber tape for motors - about the only place any customer will allow them.

I could have used the crimp-sleeve wrap in my work in what seems like a lifetime ago. While working a a wireline analyst, we often did double duty as the person who got to push the "bang" button on well perforating jets. Most of these explosive jets were assembled on open carriers and went into acid loaded cased holes with only tape to hold them to the carrier. The jets were ignited by mine type pirma blasting cord which was ignited by a simple , also mine based, crimp on copper blasting cap. For wiring these caps to our wireline firing head, we were given just Scotch 33 plastic tape and told to twist the wires tightly together, apply lots of the tape, and get to the zone to perforate very quickly, before the acid got through the tape to the wires. We actually managed to have about a 90% success rate with that. What you have listed would have upped that to near 100%, but the cheap wireline companies would never have spent the money for them. We actually bought the Scotch 33 tape with our own money, because what we were given to use came form the 99 cent rack at the local department store.

Ah! Found this in the small print: "feature#3 Standard Package 50 Per Box"

But it's pretty unclear, as they are priced "each" rather than "per box".

I agree that is a very poorly constructed web page.

It is price per box,obviously (at least to me).

I cannot imagine anyone paying that price per piece.

Look for other suppliers,and you can find better prices as well as better information.

Yes you can go very wrong with soldering. Depending upon the type, solder starts to soften around 360ºF and is fully melted around 420ºF, temperatures that are easily reached in the confines of some resistance heating appliances.

Stainless steel crimps are used because they don't oxidize, anneal, and/or creep under repeated high temperature cycling.

Redneck:

I do believe that the Toyota thing was finally attributed to software. In fact, they finally figured out that applying the brake and using the accelerator at the same time would fix the anomoly when it occured.

stupid

Here is another link you can review:

http://www.autosafety.org/sites/default/files/imce_staff_uploads/Tin_whisker.pdf

Sorry for the delay in replying - reply notification went to spam.

Thanks for all the ideas. I will either go will a high temp crimp and better crimper, or one of the high temperature screw terminal connectors. Will update when complete.