would it be possible to make one at home?
Ceramic resistors work just as any other resistor does. The trick is ceramics can resist a high heat, higher than other materials. It can get to be several times hotter than metal and still not melt. 1500 deg C or so. Don't be confused though, cermaic does not conduct heat well, it is not a good heat transfer material. It is for that very reason that they are used in circuits. 1. Cermaics have a high ability to store energy. It takes a lot of energy to heat them up. So they don't get hot quickly, like say a metal. 2. Ceramics don't conduct heat well. This means heat won't escape to the surrounding parts and fry the rest of your circuit board. If you used metal, all that heat coming out of your resistor would shoot straight to wherever the metal connects. That's not good. This allows you to dissipate the heat from there before it travels to much. Just blow a fan on it or something. 3. They are made all over the place and dirt cheap. I definately wouldn't make one at home cause you can just hit up an electonics store and buy a good one in the resistance you need. Plus I don't know how to make one. LOL. . . only how to keep them cool so they work properly. Anyway hope that helps.
How would electrical current be in contact with your water pipes? We have used a combination of those types of straps on both water lines and hot water heat lines some of which have been here since 1976 and some are newer. Because the stuff is cheap, most of the time we just made a support sling of it and nailed both ends to the joists. You should not run electric service wires through the same holes in joists or studs that water lines are using, that would be foolish and dangerous. Other than that I think you are over thinking this.
Ceramic resistors just like their carbon or metallic counterparts have semiconductor impurities added to the mix that determine how much current is going to pass through it. The nature of the ceramic is that it can handle more heat.
Ceramic resistors are wire wound resistors that are incased in a ceramic material to dissipate heat generated by power dissipation. They are used for high power applications such as power supplies. The ceramic does not determine the resistance; it's only there to dissipate the heat that results from the power in the wire. They are so inexpensive that there would be no reason to make one at home.
You can use simple plastic clips for copper tubing or brass rings with brass backplates are often used in the trade. These are fixed using normal screws and wall plugs if going into brick. Also ensure your pipework has adequate earth bonding.
