As a former electrical contractor for more than 30 years, the motto in my company was “failing to plan is planning to fail.” This cannot be truer when you are planning to build in Costa Rica.
Costa Rica has adopted the U.S. National Electric Code (NEC) but to date has no means of enforcing it. The electrical engineers do a good job of preparing the plans according to NEC, but the workers are not trained and most of the materials needed to comply are not available in local electrical supply stores or ferreterías. Thus it falls upon the owners to attempt to ensure that the contractors do the electrical installation correctly. The following is a guideline of things to watch for.
Grounding is the most important aspect of an electrical system. All metal parts of an electrical system must be grounded. This means that the ordinary metal boxes, attached to plastic conduit systems, must have a ground wire attached to that box. To do this, you need to buy U.S.-type boxes that all have a provision for this connection.
The most reliable boxes are U.S.-made. The code requires that all materials used be UL (Underwriters Laboratories) approved. Some ferreterías here carry these boxes (4×4 only), but you must ask for the U.S. type.
Only three box choices are available here, while in the United States you have dozens of choices, depending on the application. It would be best to ask a qualified North American electrician for the exact description or catalog number before ordering.
All plugs must be of the grounding type and must be connected to the ground wire also. All plastic conduits must contain this ground wire as well.
Using the correct size of electrical boxes is very important. The rectangular box used here is only legal for use with one conduit entering the box. All other boxes in the loop must be 4×4 inches with an appropriate extension ring or the correct 3” or 4” octagonal box to attach the plugs or switches. These rings will need to be imported from the United States, which can be as easy as going to Home Depot or an electrical supplier online. Again, it’s best to check with a qualified person before ordering, as many styles are available.
Boxes must be used for all splices or termination of wires. Dangling a piece of cord out of the ceiling for a light fixture is not acceptable. There must be a box in the ceiling, properly supported, with an extension ring designed for the installation of light fixtures or the correct octagonal box. Again, this will require the importation of the boxes and/or rings. Bear in mind that none of the boxes made here comply with the NEC.
Using plastic conduits made here. The thin-walled plastic conduit available in Costa Rica can only be used underground or encased in concrete aboveground. They cannot be used in (combustible) metal stud and gypsum walls, attic spaces or surface mounted indoors or outdoors.
The only option available here is conduit of the metal type known as EMT (electrical metallic tubing). You cannot mix different types of conduits without the proper adapters; this means that the practice of using EMT connecters on plastic conduit is not allowed. The connecters and couplings must be of plastic and be approved for use on plastic conduit. Plastic conduits installed belowground must be a minimum of 18 inches deep unless protected by a concrete slab, paving or the like.
Installing conduits (and other lines) in block walls. The blocks have cells designed for the installation of rebar, conduits, water lines, drain lines and so forth. The practice here is to erect the walls and stucco them first. The subsequent channeling of the walls is time-consuming to cut and patch and, in some cases, may damage the structural integrity of the walls. The boxes should be installed within the cells and adapted with a
1 1/2 to 2” ring to bring the outlet flush with the surface.
Color-coding of all wires is extremely important. Green can be used only for ground wires; white for the neutral wire; and red and black for the “hot” wires. Colors cannot be changed at any time from the panel to the end of the circuit. Blue is never used in a residence. Odd-numbered breakers are for connection of the black wires, while even-numbered breakers are for the red wires. No exceptions.
Splicing of wires. Twisting the wires together and wrapping them with tape is never permitted on 120-volt or higher circuits. A “wire nut” or similar approved connector must be used. You should not, however, twist the wires first when using wire nuts. When connecting a plug, switch or light, you must leave six inches of free wire from the device to the box to allow for future maintenance.
What should be done at the main service/ meter location? Do not use the typical, plastic, open knife switch so common here. These are totally illegal for use anywhere, especially at the meter. Use a metal-enclosed main circuit breaker that is marked for use as service equipment. If you have a metal roof, the conduit must extend high enough so the connections by the utility company are at least eight feet above the roof to avoid electrocutions to the roof.
Richard Beck has been in the electrical construction industry for 49 years. In the United States he was an electrical contractor for 30 years and a contract administrator for 12, and also worked with his tools as a union electrician. He taught evening classes for five years training electrical apprentices and has a lifetime teaching credential for this specialty from the University of California. He has lived in Costa Rica for five years. To contact him, call 249-4893 or e-mail firstname.lastname@example.org.