An incomplete, helpful guide to not burning down your business.
Introduction
If you are reading this, you probably own an escape room or you want to build one. This guide aims to address the most dangerous and common issues in escape room wiring. It should be understood that the National Electrical Code (NEC) and your local ordinances should always be followed, but in practice, as soon as the inspectors leave and you get your occupational license, people tend to do whatever they want.
AC Wiring
AC is a name for the high voltage, high power electricity we commonly use in our houses and business. AC technically only describes one aspect of the electricity. Alternating Current. This electricity flows in waves, 60 Hz (Hertz or times a second) and is great for lights and transformers, but not great for electronics.
To be specific, the electricity in America is 110 Volts, AC. I’ll use ‘AC’ in a very general sense to represent this. It is usually limited to 15A (amps) or 20A based on the breaker limit (look at your breaker). 15A circuits use 14 AWG (American Wire Gauge), 20A circuits use 12 AWG. So here is why this is important. A circuit breaker is a safety device. NEC says 14 AWG wire can safely handle 15A. Safely means it won’t overheat, melt, catch fire, etc.
So, if let’s say you extend one of these circuits with some 20 AWG wire you have laying around (which is smaller and can’t carry as much current) to run a small prop. If that prop shorts out, the 20 AWG wire will have to carry the 15A for a period of time and it’s likely to melt, overheat, and catch file. LESSON: Always use the same wire gauge through the entire branch of the circuit.
Standard single phase AC power, 110V in the USA, has 3 wires. Hot (carries the current), Neutral (current return), and Ground (references the Earth, 0V). Neutral and Ground are connected at your panel. (Not your concern. I hope you aren’t in the panel, please get an electrician.) I bring this up so you know that only the Hot (Black wire in the US, 110V systems) is the one that kills you. The other two should not have any voltage on them if properly wired referenced to ground.
AC in Escape Rooms
Most people are familiar with AC current as it’s what we have in our homes; props and decorations are routinely pulled from the commercial environment, so it’s natural to just want to run 110V AC into a room… but the best practice is to prevent all access to these outlets inside your rooms.
Common sense may seem common, but in an environment where players believe anything may be part of the game, it’s your responsibility as an escape room owner to prevent access to anything dangerous and to assume players will interact with everything in the game space. Some irresponsible owners have even designed puzzles involving faux electrical outlets, complicating safety for everyone else.
You bear full responsibility for the safety of the public when you invite them into your business. Not putting AC fixtures, props, or appliances in your room helps keep the room safe. This doesn’t mean removing fluorescent lights in your drop ceiling, but it does mean you need to pay attention to objects you may not even have considered, like the potential that players might try to remove light bulbs from a table lamp, creating a hazardous situation.
The use of GFCI can increase the safety of an AC circuit. They are just not for wet locations. These ingenious devices look for electricity leaving the system. A person could be in the path where the electricity is leaving the system and this will cut power when it detects that fault state.
If you must…
AC Wiring Key Points
- Minimize use of AC. Overhead fixtures are OK, but cover up plugs and convert everything else to low voltage DC.
- Run your grounds. They are there for safety. It doesn’t matter if they aren’t needed for function.
- Do not use Romex, it’s for houses. Use ENT (metal or metal wrapped pipe) or the blue ‘smurf pipe’ if allowed by code, other approved enclosure for running AC current. Or hire an electrician.
- Restrict, tether, mount, strap, etc. your wiring. All of it (DC too). Keeping wiring from getting yanked out of their termination point increases safety a lot.
- Use a GFCI. They are just not for wet locations. They increase the safety of the circuit.
- Use proper junction boxes. Don’t leave a connection in midair with wire nuts on it.
- In a box with mixed voltages (AC and DC), keep the AC as far from the DC as possible. You should be able to draw a virtual line down the path where they are kept separate. Generally, components that handle both AC and DC have an isolation rating of 1000V. If it doesn’t, don’t use it.
- Use approved power supplies. UL/ETL labels on power supplies will ensure you are using a quality product.
- Keep wiring gauge consistent. Basically, you should never be using anything less than 14 AWG wire in a 15A circuit. No less than 12 AWG in a 20A circuit. Don’t use larger than 20A circuits unless you REALLY know what you are doing.
- Switch the hot. If you are going to switch AC, use a device designed for it. If you insist on using a relay off eBay you found for $3, make sure you are switching the leg that has power on it. A proper relay will have an isolation rating to ensure it’s safe. I would also consider switching both sides of the circuit for complete isolation.