This should be a fun DIY question! Assuming I'm well under max load and have circuit protections in place, am I breaking codes/laws regarding insurance and liability if I, for example:

1. Make my own or modify a lamp - plugs into outlet

2. Run LED light strips around the patio - mount the AC/DC transformer to wall - plugs into outlet

3. Build my own arcade machine which is a wooden box full of computer components, a monitor, amp, speakers, LED lights, USB hub, all plugged into a powerstrip mounted inside the wooden box, or maybe my own distribution board so I can mount ON/OFF switches - plugs into outlet

 

So long as you follow code requirements as you do those projects you should be fine.

 

One thing I figured I'd mention here is it's against code to daisychain power strips or plug them into an extension cord.

 

You might have an issue with your homeowners insurance company when you construct light fixtures, even fixtures that are plugged into wall receptacles.

The fixtures would of course not be rated by an official testing agency such as Underwriters Labs.

A common pitfall with homemade light fixtures is bulbs in small closed compartments and/or too close to flammable materials. An example might be an illuminated tic tac toe board as a wood frame with light bulbs in the nine play positions.

 

Got a code citation for that, Justin? I agree it IS poor practice but I have never seen an actual code prohibition other than maybe falling under the prohibition of substituting extension cords for fixed wiring.

 

Great info here thanks! Does the code go into homemade devices? I'm branching out from computer building -- when you build a computer, you buy a case, the DC components, and plug them into power supply (AC/DC converter). Some people do soldering and splicing. Sometimes water cooling. I bought power supplies with fault protection for LED lighting but now I'm second guessing just mounting them in a game box or on top kitchen cabinets or on the ceiling, without some documentation to reference.

On the power strip question, it's odd daisy chaining is an issue when you can buy power strips with 15 outlets, giving you a total of 30 outlets. Perfectly safe for when the house guest decides she needs to blow dry her hair in front of the TV. In the computer world, it's common to plug an expensive battery backup unit into a fuse-only (no surge protection) power strip as an extra way to protect the battery in a surge.

 

NEC does not discuss anything that plugs into an outlet or receptacle. If you were building and selling items, UL would be the next step, but since it's just a hobbyist pursuit, it's not really anything you have to worry about.

I would suggest always looking at other similar devices and try to replicate them in terms of the type and size of wire, strain relief, and things you may not have even thought about. Another thing to always remember is to ground anything that's metal. That will ensure a loose wire won't electrify the case and anyone who touches it.

Whenever possible, use low voltage. It's easier and much safer. Using pre-made wall wart power supplies take all the risk of using 120v away and you can just focus on whatever you're working on and less of the electrical safety.

 

> it's common to plug an expensive battery backup unit into a fuse-only
> (no surge protection) power strip as an extra way to protect the
> battery in a surge.

Fuses do not protect hardware. Fuses blow after hardware is damaged. So that damaged hardware does not create a fire and threaten human life. Fuses are for human safety; not for transistor safety.

Many appliances are powered from wall warts. Why? Because all electicity after the wall wart is low voltage - does not require additional safety considerations. Same for your projects. Purchase a power supply (what you mistakenly called a transformer) that already meets UL and other safety criteria (as Zorfdt mentioned). Then those low voltage devices (ie LEDs) do not require numerous human safety precautions (that you apparently do not know about). Then you can spend more time learning (doing) those projects.

Also accurately noted by others - never daisy chain power strips. Daisy chained power strips are another threat to human life. Rather than go into the human safety reasons that have resulted in fires, instead, just do not do it. Every power strip should make a direct connection to a fixed wall receptacle.