Ask The Experts


I am selling my house and just received the report from the buyer’s inspector. He says that I have water damage in my electrical panel, requiring replacement. I know that there has never been any flooding in my house. How is this possible, and what can I do about it if it’s true?

Water entry into electric service panels is actually very common, and sometimes very dangerous. The usual path of entry is from the exterior and is due to problems with the entrance cable. This large cable carries the current from the wires coming to your house down through the meter and into your service panel. Unfortunately this cable often also carries rain water down into your fuse or breaker box. If the cable jacket, whether plastic or coated cloth type, is worn, or if the putty seal at the top of the meter is loose or missing, water can get into the cable and flow down into the electrical box. To make matters worse, if the cable enters at the top center of your panel box, the water drips right down through the breakers or fuses and corrodes all of the connections.

Water and electricity don’t mix well. A wet panel can be major shock hazard, but in addition the corrosion can result in poor connections which can cause arcing and a fire hazard. It may be that the corrosion is minor and repairs to the entrance cable and panel will suffice, but if the corrosion is heavy, replacement of the entire service may be necessary. Call an electrician for a full evaluation and replacement if necessary.

I have several lights in my house that periodically flicker. I have tried screwing in the light bulbs better, but this has not helped. Should I replace the light fixtures?

Flickering lights are a warning signal. They indicate loose electrical contacts or connections. Electric current jumps across the small gaps caused by loose connections. This is called arcing, and results in heat generation. We often see evidence of loose connections and arcing when we inspect electrical panels, but poor connections can occur anywhere in the wiring, including junction boxes or outlet boxes at receptacles and light fixtures. The evidence of arcing is scorched wires and melted wire insulation, but this may be hidden. The arcing can become worse over time, especially if the affected circuit becomes more heavily used. The result can be a devastating fire.

The fact that you have several flickering lights may indicate that you have aluminum branch circuit wiring. Aluminum wiring has been found to be especially prone to loosening at connections and has been implicated in some fires. Aluminum wire was commonly used in the early 1970’s due to a copper shortage. Aluminum wire for residential branch circuit wiring fell out of favor due to this problem within a few years and has rarely been used since, despite improvements in available connecting devices. If you suspect that you have aluminum wiring, even if you don’t have flickering lights, you may want to have the wiring connections inspected and repaired or replaced as necessary with modern connectors.

In any case, if you have flickering or dimming lights, or intermittent operation of any outlets, you should have the problem diagnosed and corrected by a licensed electrician as soon as possible. Don’t take chances with electricity and loose connections.

I am building a bedroom addition on my house. I understand that I am supposed to use a fluorescent light in the closet. Can I use an LED light fixture instead?

Ultimately this is a question for the code enforcement official having jurisdiction in your area. Building, fire, and life safety codes are normally developed and available for adoption by states, municipalities, etc. to use in regulating new construction practices. The process is ongoing, resulting in different codes being in force in different areas at different times, which are then subject to interpretation by locally authorized code enforcement officials.

The point of the rule regarding the use of fluorescent fixtures in closets is to reduce the likelihood of a fire caused by the greater heat from incandescent bulbs. A high percentage of residential fires originate in closets. Any closet fixture must be placed so that it is not likely to be impacted by items being moved in or out of the closet, and so that stored items are not likely to be stacked up to, or against, the fixture. We are not aware of any codes that presently reference the use of LED fixtures in closets, but you are right to think that ultra-cool LED fixtures would be a good choice, if protected from impact.

In older homes that have old exposed light fixtures, simply installing new compact fluorescent bulbs in the existing fixtures may not be ideal, but would sure be safer than leaving old incandescent bulbs in place.

I have been noticing rust at the bottom of my electric panel in the basement for some time. Then just the other day I actually saw water dripping out. Where is this coming from and what should I do?

Water entering into an electric service panel is actually a very common occurrence. From our home inspection experience, about one in five electric service panels shows evidence of some water entry, and many of these panels have resultant significant damage. This is obviously not a good thing. Water in the electric panel can easily result in a serious shock hazard for anyone accessing the panel to change fuses or reset circuit breakers. In addition, corrosion of the electrical contacts and connections from the chronic moisture causes arcing, overheating, and fires.

The most likely source of the water is from rain entering the meter box or the electric service cable on the outside of the house and then traveling within the electric entrance cable jacket down into the panel box in the basement. The water sometimes enters from the weatherhead where the service drop from the pole meets the house, but more often the water entry is caused by a deteriorated jacket on the entrance cable or a deteriorated seal where the cable enters the top of the meter box. Sometimes the bottom of the meter box is totally rusted out from chronic water seepage. Your electrician should be called in to replace the electric service cable or renew the seal at the top of the meter box, and then to assess the extent of the damage in your circuit breaker or fuse panel. If you are lucky and the electrician who originally installed your electric panel designed the installation well, the water may not have actually contacted your fuses or breakers, and the connections may still be in adequate condition. However, if significant corrosion has occurred at the contacts and connections, you may need a whole new service. This is a potentially serious concern and should be addressed as soon as possible.

The inspector for the people buying my house reported that I had oversize fuses in my electrical panel. How do I know which ones to change and what are the correct sizes?

Fuses are designed to protect the electrical wiring in your house from too much current flow and resultant overheating and fires. By safely burning out when too much current flows through, fuses prevent the wiring from becoming too hot. Oversize fuses are potentially hazardous and should be replaced with the proper size. Most fuses come in one of four sizes, or ratings. The ratings are for 15, 20, 25, or 30 amps. The smallest of these fuses will only allow 15 amps of current to flow through before it will burn out. It is designed to protect the smallest diameter wiring. Each larger fuse size corresponds to a heavier gauge of wire. Almost all 120 volt branch circuits are wired for either 15 amps or 20 amps. If you have 25 or 30 amp screw-in type fuses in your panel, they are probably oversized and are not adequately protecting the wiring from potential overload. In most cases the only circuits that might require 30 amps are for heavy demand equipment like electric water heaters, well pumps, or clothes dryers. These fuses would normally appear in pairs and should be connected to visibly larger wiring.

It is difficult for the novice to discern the difference in wire size between wiring capable of handling 20 amps and wiring capable of handling only 15 amps. The safest approach would be to install only 15 amp fuses. If they do not burn out under normal use, then you are all set. If any of them do burn out, you should call in an electrician to help you determine the appropriate size for those circuits. It may turn out that the affected circuits are overloaded and more circuits should be added to handle the load. Overloaded circuits are especially common in kitchen wiring because of the number of electric appliances that may be operating at any given time.

To complicate things a little further, while most screw-in type fuses are interchangeable, there are special sleeves that can be installed in the fuse sockets that will only allow the proper size fuses to be installed. These are called Fusestat adapters. Fusestat fuses have a smaller diameter ceramic, rather than metal, base. Make sure you buy the right type by taking one of the old fuses with you.

While fuse boxes may be perfectly safe as long as the right size fuses are installed, they probably indicate that you have a fairly old electric service. Updating to a modern circuit breaker type electrical distribution panel and service would be more convenient, would help ensure that the circuits are properly protected, and would replace any potentially worn or damaged older components.

You indicated in a previous article that electrical wiring that had been submerged would probably be acceptable for re-use, but I recently read somewhere that it should be replaced. Do you have any further info on this?

It is true, as we stated earlier, that in some instances electrical wiring that has been submerged may be reused. And, we have seen numerous instances as home inspectors where Romex wiring that had been chronically wet or submerged was being successfully used for many years after its immersion. However, in most instances it is better and safer to replace the wiring. The International Association of Electrical Inspectors and the National Electrical Manufacturer’s Association appear to be in concert in firmly recommending against the re-use of any electrical wiring that has been submerged in flood waters, unless the wiring has been rated for wet locations. An example of wiring rated for wet locations would be UF type wiring, which is designed for exterior exposure or ground contact. Even when the wiring and its components are rated for wet locations, professional evaluation of the wiring and all connections is advised.

Older wiring such as types with woven cloth insulation are much less resistant to water damage than newer PVC plastic insulated wiring, and should definitely be replaced if subjected to flooding. Immersion of any electrical components, including PVC insulated Romex wiring, in flood waters containing unknown chemicals and contaminants, may cause deterioration of the insulation or the metal conductors, resulting in failure of the wiring and wiring components over time. The paper wrapping around the bare equipment grounding conductor in the wiring may absorb water into the cable, causing future corrosion if wiring connections were submerged. Given the potential corrosive character of flood waters, we have to recommend that the wiring be fully replaced if it has been submerged. However, PVC plastic insulated wiring which has merely gotten wet or been submerged only briefly in clean water without immersion of the connections, such as during construction, would not be compromised and may be used without concern for future degradation.

My house was built in approximately 1915 and has knob-and-tube electrical wiring. I am getting conflicting opinions about whether it has to be replaced. What do you recommend?

Knob-and-tube wiring is the earliest type of electrical wiring, and was installed into the 1920’s. This wiring normally had a dark cloth type insulation over the wires. The hot and neutral wires were run separately, usually a few inches apart, rather than bundled together in a single cable like modern Romex wiring, and there was no ground wire. The wires were secured with ceramic holders, or “knobs”, that look like miniatures of the ceramic insulators on old electric poles. Where the wires pass through framing they were protected by ceramic tubes, hence the name for this type of wiring.

Technically, if the wiring remains in good condition physically, if it has not been buried in insulation, and if it has not been tapped onto by any later wiring, it can be considered acceptable. However, knob-and-tube wiring that meets all those conditions throughout a house after eighty years is pretty rare. The insulation is often deteriorated, especially at old enclosed ceiling light fixtures. It is commonly buried in insulation in most homes, as we try to prevent heat loss. And it is usually extended with newer wiring, since electrical outlets in homes built in 1915 were few and far between. In addition, since the old wiring had no ground wire, any equipment requiring a grounded circuit couldn’t be safely plugged in to an available wall receptacle. Further, many of the fixtures that remain from that era are inherently unsafe, due to bare connections, or too easily accessed live components. Fuse boxes from that era contain several unsafe features, including fuses on neutral wires. A burned out fuse on a neutral wire will cause a circuit to appear to be dead, or de-energized, when in fact it would remain “hot” and potentially hazardous to the unwary.

We wouldn’t expect water pipes that are almost a hundred years old, or much else in the house for that matter, to remain in good, safe working order after so many years. There is no reason to expect electrical wiring of that age to be free from problems. We recommend updating the wiring.

My house was built in approximately 1955. Some of the wiring in the house has some kind of painted cloth covering, and the rest is covered in a flexible metal. Is this wiring safe, or should I have it replaced?

This wiring is not all that different in its basic characteristics from modern wiring. Unless we know that the house has been flooded or has been in a fire, well installed and well maintained wiring from this era should remain in acceptable condition. In fact, the wiring in the flexible metal sheathing, referred to as BX cable, is generally safer than modern Romex wiring because nails won’t penetrate it and rodents can’t chew through it.

Some of your old wiring may not have a third, uninsulated wire, called the branch circuit ground wire. Without a ground wire, appliances that require a ground may not be able to be safely used. (These are typically metal bodied appliances with a third pin in the appliance plug.) A three prong to two prong adapter can work safely in such a situation only if the third pin is connected to the screw in the center of the receptacle plate, and if the wiring includes a ground wire. If some of the wiring does not include a ground, you may wish to update this portion.

Rather than being concerned about the wiring based on its age, you should focus your concern on its condition. Is the wiring well secured, are there any uncovered junction boxes, is the wiring frayed or corroded, are there connections made without being housed in junction boxes, is wiring in a location where it is likely to be damaged, are receptacles damaged or uncovered, are receptacle or switch boxes loose, or are the plugs from appliances too loose in the receptacles, do lights flicker or dim. Jury-rigged wiring is very common. Bad wiring is especially common in basements and above suspended ceilings. If any of these conditions exist, an electrician should make repairs. Electrical fires are way too frequent to take chances with your wiring. If you have any questions about what you see, call in a professional to take a closer look.

I have been told that my house has aluminum wiring and that this is a problem. How serious is this, and what should I do about it?

For a few years in the late 1960’s copper became scarce and more expensive. In an attempt to reduce costs, manufacturers of electrical wiring produced aluminum branch circuit cable. The aluminum wiring is insulated with the same plastic insulation that we have come to recognize as modern Romex. The connections should be inspected to determine if the wiring is actually aluminum. If you see plastic sheathed 12 or 14 gauge wire that is a dull silver color rather than copper colored, it’s aluminum. Most of the aluminum branch circuit wires we are likely to find in a house from the late 60’s or early 70’s will have been used for lighting circuits only, on 15 amp breakers.

The problem is that branch circuit aluminum wires have been implicated in electrical fires. This is because the wires expand and contract with current flow and temperature changes, causing connections to potentially loosen. As electric current tries to bridge a loose connection, the resistance results in excessive heat build-up and potential fire. Woven strand wiring does not have this problem because the multiple strands are more capable of absorbing the expansion and contraction. Almost all modern electrical entrance cables into the house are aluminum, as are other typically 220 Volt woven strand cables to sub-panels or major appliances, so don’t be alarmed if you see these aluminum wires.

There is a divergence of opinion on the best way to deal with residential aluminum wiring. The Consumer Product Safety Commission recommends the use of a special crimping tool to connect aluminum to copper in order to complete the connections at the devices with copper. Other authorities have approved special wire nuts for this purpose. The actual incidence of residential fires caused by aluminum wiring is thankfully quite low, given the large number of homes that have this wiring. Our own recommendation is to, at minimum, have the connections fully evaluated by a licensed electrician, with reconnections made as necessary.

I am selling my house. The inspector says that I have open grounds at the electrical outlets. What is the best way to correct this?

The best way to correct “open grounds” depends on what type of electrical wiring you have. You may have noticed that some or all of the receptacles that you use to plug in appliances, have three holes. The two vertical slots are for the current that runs through the appliance and provides the power. The third hole, which is essentially round, is supposed to be connected to ground. It is a path for current to take if the body of the appliance becomes electrified. If the body of an appliance becomes energized and there is no ground, the current will potentially flow through you to ground when you touch the item. If the appliance is connected to ground, any current in the appliance body would trip the circuit or blow a fuse, shutting down the power and keeping you safer. An “open ground” means that the ground wire either doesn’t exist or is not hooked up to that third hole in the receptacle. An amazing number of modern grounded type receptacles are not actually grounded.

If the house is relatively modern, meaning from the mid 1960’s, the receptacles should have been grounded and a wire is probably loose, which is easily correctable. If the house dates from the mid 1940’s there should be ground wires connected to the outlet boxes, and updating will be easy by simply wiring the receptacle ground connections to the boxes. Wiring installed prior to that date may not be capable of accommodating a grounding path. In that case you have three approaches available. One is to convert the receptacles back to the old type with only two slots. These are what the house originally used. They are less convenient but will be safe if used as intended, meaning that appliances that require a ground should not be plugged into these receptacles. A second option is to rewire the circuits from the main panel to the receptacles. This is likely to be very expensive. The better alternative, short of rewiring the house, would be to install GFI protected receptacles. These come equipped with test and reset buttons. They detect current flow to inappropriate locations, such as your body, and break the circuit. They are an acceptable substitute for true grounded receptacles, and they are relatively inexpensive.