A vintage light fixture in the author’s home. (Annie Schlechter )

I like to buy vintage light fixtures — sconces, lanterns, pendants and chandeliers — for my decorating projects. I find that vintage fixtures are often better-made than new fixtures, I prefer their patina, and I appreciate the distinctive, one-of-a-kind quality they add to rooms. Online shopping platforms such as 1stDibs, Etsy and One Kings Lane have made it easy to find everything from an early-20th-century French crystal chandelier to a ’60s Sputnik. But before you click the “buy” button on a vintage fixture, there are a couple of things you need to know.

First, always ask whether a fixture has been rewired. Sometimes sellers note this in the product description, but if that’s not the case, call or email the seller to find out. There are a number of reasons to have a fixture rewired. It could be that the wiring is European, in which case it is not compatible with U.S. voltage, or it could be that the wire is dried out and brittle — a potential fire hazard.

Rewiring isn’t a big deal; it just means more time and money that you will have to invest in the fixture. Any reputable lighting store can do the work for you. Artisan Lamp has been selling, rewiring and repairing antique fixtures in the D.C. area for 37 years and is a favorite of many local designers and antiques dealers. According to the store’s owner, Cyrus Manaf, rewiring starts at about $15 per fixture.

Second, if you are planning on using the fixture in a newly constructed home, you will probably need to have the fixture UL-certified or you won’t pass an electrical inspection. I learned this the hard way when an electrician refused to install a non-UL-approved vintage fixture in a client’s home.

UL stands for Underwriters Laboratories, a 122-year-old company that tests not just light fixtures but also many other items, including blenders and suspended ceiling tiles, for safety. According to UL’s consumer safety director, John Drengenberg, more than 22 billion items carry the UL seal.

A vintage light fixture in the home of one of Elizabeth Mayhew's clients. (Peggy Anderson)

To get a light fixture approved by UL, you need to send it to someone who subscribes to UL’s services. (Translation: The person or company pays UL a subscription fee.) Typically, UL subscribers are large manufacturers. This is how it works: A manufacturer sends its product to UL, and UL conducts a series of safety tests. The UL tests make sure that all of the components are working properly, that the fixture is grounded and that the proper grade of wire was used. Once the item is deemed safe, the manufacturer is allowed to use the UL stamp on all future production of that item. (To be clear, not every item that gets the stamp has been tested.) Companies continue to pay UL yearly fees to maintain the relationship, and, in turn, UL reserves the right to spot-check the manufacturers’ facilities whenever it wants.

In the case of lighting, electricians, inspectors, designers and architects use the UL stamp as a safety shorthand; they view it as protection against being held liable should something go wrong. For new construction, UL certification becomes all the more important when building inspectors are assessing a new project for a certificate of occupancy. This was the situation when the electrician I hired refused to hang my client’s vintage light fixture; he did not see the UL stamp on it, so he would not hang it for fear that he would be cited by the building inspector and thus jeopardize his license.

The problem is that it’s not easy to find someone who can grant a vintage fixture UL approval. Although Manaf uses top-of-the-line UL-approved parts (sockets, wires, etc.) to remake fixtures, he is not certified to attach a UL-approved sticker to that fixture.

Unfortunately, UL does not have an adequate resource search on its site. What it does have is a directory of subscribers, but there is no geographic filter. The directory is helpful only in confirming that someone who says they can give UL approval actually can. If you do find someone who says they can do UL certifications, Drengenberg suggests cross-checking the business name in the UL directory. He warns: “Watch out for people who claim to be able to give the certification. They could be counterfeit.”

The existence of UL bootleggers is not surprising: Getting UL approval on a single fixture can be pricey. I recently asked three UL-certified inspectors how much it would be to have a five-socket fixture certified. Their prices ranged from $195 to $650.

Ultimately, only you can decide whether you are comfortable forgoing UL certification for a fixture. It is absolutely legal to sell, buy and install non-UL-approved fixtures, and a large percentage of designers, antiques dealers and electricians balk at the UL requirement, saying that it is unnecessarily rigorous. In fact, when I spoke to a number of antiques dealers, they all said that it didn’t pay for them to have fixtures UL-approved because customers demand it only about 5 percent of the time.

Mayhew, a “Today” show style expert and former magazine editor, is the author of “Flip! for Decorating.”