1. Improper wire junctions/terminations – where two or more wires meet, this wire junction (splice) is required to be wire nutted and enclosed in an approved junction box. This is required for several safety reasons, namely to help limit a shock hazard or to help contain a small fire. Where a wire stops (terminates), it should also be wire nutted and enclosed in an approved junction box. Even if the wire is no longer in service or live, years down the road someone could connect something on the other side of the home and all of a sudden this unterminated wire can become energized, now a shock hazard. It is best to be pro-active and properly protect the wire splices or terminations now.
2. Buried Wiring – To safely bury wiring underground, only wiring approved for direct underground burial use, such as a rigid conduit or UF-rated Romex/NM cable should be used. Imagine burying household Romex/NM cable in your back yard, forgetting it, and hitting it with your shovel next spring when planting flowers. Ouch! Hitting conduit with your shovel will alert you to the fact of underground wiring, and also prevent you from slicing through the wiring and getting the shock of your life. If buried in rigid conduit, it should be at least 6" deep; if direct burying UF-rated Romex/NM cable, it should be at least 24" deep.
3. Ungrounded receptacles – in the early 1960s, electrical codes changed to introduce 3 wire grounded receptacles to residential homes. The grounding conductor (the round pin in a 3 prong receptacle) is designed to give electricity a safe place to discharge should something go wrong with an appliance or in case of a nearby lighting strike. Homes built before the mid-1960s were not normally wired with 3 conductor wiring, but rather were wired with only a 2 conductor cable. 2-wire ungrounded receptacles are not a safety issue themselves, however many modern electrical appliances (such as surge protectors, refrigerators, TVs, sump pumps, computers, etc.) require a grounded circuit for intended function and for safety reasons. A surge protector, for example, has no surge protection whatsoever if it is unplugged into an ungrounded receptacle; many homeowners are totally oblivious to this fact and don't know the hidden risks.
From my experience, people often replace the older 2 wire receptacles with modern 3 wire receptacles, but not rewire these receptacles. Unless these receptacles are rewired with modern grounded wiring (or a special grounding conductor is connected to each receptacle), the result is an ungrounded 3 prong receptacle. Just by looking at a 3 prong receptacle, one normally assumes it is grounded which may present a wrong assumption and a critical hazard. If ungrounded 3 prong receptacles are present, there are several ways of correcting the issue. The receptacle can be changed back to a 2 wire type, the wiring to the 3 prong receptacle can be replaced with new Romex/NM cable, or a Ground Fault Circuit Interrupter (GFCI) receptacle can be used (assuming it is labeled ‘No Equipment Ground’).
4. Knob & Tube Wiring – this type of wiring (see below) is the original type used in homes built prior to 1950. The conductors for this type of wiring are separated, unlike later sheathed cable that had the insulated conductors wrapped together. Knob and tube wiring needs to be closely evaluated by a licensed and qualified electrician. Because of the age and lack of capacity, it is generally inadequate for today's usage. Old knob and tube wiring tends to be brittle which can lead to arcing and fires. Also, junctions in knob and tube wiring tend to not consistent with today's wiring and safety standards. Often, knob and tube junctions are found only soldered or taped which is not sufficient per today’s standards. Also, some insurance companies will not insure homes with knob and tube wiring. A thorough inspection of the home's active knob and tube wiring by a licensed electrician is recommended, although replacement of active knob and tube wiring is most often wise for fire safety reasons.
5. Missing Wire Bushings/Clamps and Knockouts – wherever wiring enters a metal junction box, metal appliance, etc., the wiring is required to have wire clamps to protect the wiring from mechanical damage or abrasion. For example, the vibration of a garbage disposal can slowly slice through wire insulation. A shock hazard can occur once it gets to the live conductors. The wire clamp holds the wiring in place so it can’t touch the metal chassis or junction box. Sometimes, wiring is removed from a junction box, however, the opening in the junction box is left open where various objects (fingers, tools, insects, rodents, etc.) can enter. Unused junction box and breaker panel openings (knockouts), should be properly closed using filler plugs (electrical tape is NOT a proper repair).
Wiring enters this junction box with no cable clamps or bushings. The wiring must also be fully sheathed unlike in this photo.
An unsealed knockout exists in this junction box.
6. Extension Cords – We all use them occasionally, but extension cords are not meant to be used as permanent wiring. Often, people use extension cords to power things like outside fountains, garage door openers, appliances, and lighting, but extension cords are meant for temporary means; not to be used in place of what should be permanent wiring. Should power be needed where there is not currently an accessible receptacle, a licensed and qualified electrician should be consulted to install a new receptacle(s) where needed.
The National Electric Code (NEC) rule regarding maximum distance allowed between receptacles comes from the fact that they are trying to greatly minimize the need for extension cords. Since most lamps come with 6’ cords, if the maximum spacing allowed between receptacles is 12’, one should not need to use an extension cord to power a lamp if following these rules.
7. Double Tapped & Double Lugged Circuit Breakers – circuit breakers are normally designed to accept one (1) wire safely. Some brands of circuit breakers (such as Square D and some Cutler Hammer breakers) are designed to accept two properly-sized wires since they have a special clip for each wire. Terminals for more than one wire must be specifically identified for this purpose, either within the equipment instructions or on the terminal itself.
Generally, the term ‘double tapping’ means having multiple wires connected to the location where the main service cable connects at the main breaker. Double tapped wires are often lacking over-current protection which can lead to overheating and fire. Also, most circuit breaker panel manufacturers have specific torque and wire size requirements to safely allow for only the main electrical service cable.
The term ‘double lugging’ is similar but applies to individual branch circuit breakers. If only one screw exists to accept a wire, that normally means only one wire should be connected at that breaker. Connecting more than the allowed number of wires to a circuit breaker can overdraw the circuit and can also prevent either wire from being properly secured at the breaker. Loose wire connections can lead to arcing and fire. Some correction methods (depending upon the panel) include installing additional breakers or installing an auxiliary subpanel.
8. Improperly Wired Receptacles – Electrical receptacles are designed to have specific wires at specific terminals. A polarized receptacle (one with a longer vertical blade than the other blade) will allow a polarized plug to be fit into it in only one direction. The small blade (when installed properly) is connected to the hot (black) wire. The larger blade (again, when installed properly) is connected to the neutral or grounded (white) wire. The round pin is connected to the bare (grounding) wire. Circuit testers are sold at hardware stores which can identify improperly wired receptacles.
When the hot and neutral wires are reversed, the issue is called reverse-polarity and can be a shock hazard. In most circumstances, repair is fairly easy and not time consuming, but should be performed by a licensed electrician.
If the hot and ground (bare) wires are reversed (Yes, I’ve seen it happen!), it is even more of a serious safety issue and should be addressed immediately by a licensed electrician. It would also be wise NOT to use this receptacle until it is repaired.
9. Non-Functional GFCI Protection – Ground Fault Circuit Interrupters (GFCI) can be in the form of a GFCI receptacle or a GFCI circuit breaker. GFCI protection is now required (for new construction) in areas where electricity and water can potentially meet. At different points in time since 1973, GFCI protection requirements have added more locations around the home. Currently, for new construction, GFCI protection is required in bathrooms, unfinished basements, garages, exterior receptacles, and most kitchen receptacles. A GFCI is designed to monitor the amount of current going into the receptacle through one wire versus the amount of current coming back out the other wire. If a lower amount is coming out than what is going in, it assumes the difference must be shocking someone and should trip. For example, 5 Amps going in but only 4 Amps going out the other wire. The GFCI 'assumes' that the missing 1 Amp of 'missing electricity' must be shocking someone and ‘POP!’ the GFCI trips.
When a GFCI receptacle ‘trips’, the little “TEST” button pops out and shuts down the circuit. When a GFCI circuit breaker ‘trips’, the breaker handle goes from the ON position to a middle position. GFCI circuit breakers also have a ‘TEST’ button. A problem that is not uncommon with GFCI protection it that is simply stops protecting. Should a GFCI not trip when the ‘TEST’ button is pressed or the device not reset, it is best to replace the GFCI protection device. These are inexpensive but a very good safety device. Most newer GFCI receptacles have a modern safety feature that will prevent the receptacle from resetting if the receptacle is miswired line-load. The GFCI receptacle will only work after installation until tripped the first time. In theory, this is to force someone to fix the wiring flaw in order to return power back to the receptacle.
10. Improperly Wired Subpanels - Subpanels are often installed in a home if the original breaker panel is full of breakers and an extra circuit(s) is needed, if an addition is done to the home, or a detached building exists on the property. A subpanel is an auxiliary breaker panel (having 1 or many circuit breakers) that is downstream of where the home's main service disconnect (aka 'the main breaker') is located. The home's main breaker panel is the enclosure that has the main electrical service disconnection means for the entire building. Most homes have only one breaker panel that includes the main breaker and all over breakers for the home's circuits, but some homes have both. A subpanel may be a few inches from the main electrical service disconnect, may be on the opposite side of the home, or in a different building.
In subpanels, the neutral (normally white) conductors must "float" and may not be connected to the electrical system's grounding system (including the subpanel's chassis). "Floating" conductors simply means, in this case, that those wires are not connected to ground. The above condition can present a potential shock or fire hazard as objectionable currents will not be prevented. "Objectionable Currents" is electrical energy that is traveling on a metal conductor (such as a wire, metal appliance, metal pipe etc.) that is not supposed to be carrying electrical energy. This issue may also prevent proper operation of GFCI and AFCI devices.
Also, subpanels should be connected to the main panel (and/or service disconnect) with a 4 conductor feeder cable (2 hot conductors, 1 neutral (aka grounded) conductor, and 1 grounding conductor). Older standards permitted subpanels in detached buildings (a building other than where the main panel is located) to be fed with 3 conductor feeders (2 hot conductors and a single combined neutral/ground conductor) assuming a ground rod was installed at the detached building.
The issue in the above photo is the bare grounding conductor connector connected to the neutral terminal bar at this subpanel's left bottom corner. Instead, since this breaker panel is a subpanel, the bare grounding conductor should only be connected to the grounding terminal bar at the far right upper corner in this photo. The rest of this subpanel's neutral conductors (white insulation) are properly installed to the terminal bar at the bottom right corner in this photo.
Electric baseboard heaters include instructions that forbid their installation below wall receptacles because cords plugged in above the heaters can then hang down into the heaters thereby possibly melting the wire insulation and presenting a shock or fire hazard (see photo below).
Electric baseboard heater installation guidelines can be found here: http://inspectapedia.com/heat/Electric_Heat3.htm
© 2014 Matthew Steger
Matthew Steger, owner/inspector of WIN Home Inspection, is a Certified Level 1 Infrared Thermographer and an ASHI Certified Inspector (ACI). He can be reached at: 717-361-9467 or firstname.lastname@example.org.
WIN Home Inspection provides a wide array of home inspection services in the Lancaster, PA area. This article was authored by Matthew Steger, ACI - owner of WIN Home Inspection in Lancaster, PA. No article, or portion thereof, may be reproduced or copied without prior written consent of Matthew Steger.