What kind of conduit and wire should I use to hook up our patio for lights and a couple of overhead electric heaters? I've been told to buy THWN to protect everything against water here in Baltimore. Am I on the right track or is there a better way to do it?
Eric F. ~ Baltimore, Maryland
Eric, you are definitely on the right track when you choose THWN wire for a project which requires running electricity to an outside location. The THWN designation stands for "Thermoplastic High Water-resistant Nylon coated", and this type of wire is often required by code for your type of project.
The other important consideration when adding electrical circuits to your home is choosing the correct size of wire. The size of wire you need will depend mostly on the load of the electrical heaters you want to install above the patio. The current rating of the heater's power load is crucial information which you need in order to correctly size your wire. Remember, an under-sized wire can get hot enough to melt the wire's insulation and eventually catch fire, and this is one reason many local electrical codes require a licensed electrician to oversee this type of home improvement.
Although all electrical projects need to meet the Nation Electrical Code (NEC), there may also be local codes in the Baltimore area which dictate how the wiring must be sized and installed for your project. I suggest contacting a licensed electrician who can help you correctly chose which wire to use and make sure that your project is code compliant. Good luck with your project and enjoy your new patio!