Annoying buzz or hum - cause and solution

[austin]

There is a buzz or hum that appears to originate in or around the electricity meter on the outside of the house. When the house is otherwise quiet, I can hear it inside the house and feel the vibration through the floor. The buzzing sound is much louder when the electric furnace is on. What causes this and what is the solution?

[mrcaptainbob]

Meter disc out of balance????(sorry).....Being a wise-acker and not offering any help.....[B)]

[HayZee518]

The buzz or hum is normal operation of the meter. The meter is made up of an iron winding with copper coils around it. The 60 cycle hum is the power going through the coils as it is measured. Like some induction motors there is a "shading" coil made of copper. These shading coils sometime loosen up and vibrate causing a hum or buzzing. Call your utility and have them change out the meter with a solid state meter if they have them. Otherwise just change the meter

[austin]

I've been turning the heat down to 17 degrees celsius before I go to bed and for the last 6 weeks I've been waking up every morning around 3:00 a.m. and having trouble getting back to sleep. I wasn't aware of any noises, particularly, and I normally sleep well, especially when it is cool. The other day, I finally figured out why I've been waking up.

I have heard a hum in the house during the day from time to time but couldn't find it's source. I had gone outside to see if it was coming from the meter or the power line but when I got out there, there was no hum anymore. The other day, I happened to be standing outside near the meter when it started to hum. Ah! The house cools down to 17 degrees around 3 a.m., the furnace goes on for the first time since I fell asleep, the meter starts humming and wakes me up. Now, when I wake up, I listen for the hum and the vibration and sure enough, there it is every time.

[HayZee518]

The meter socket is solidly fastened to the house siding so the wall space acts as a resonator and amplifies the sound a bit. Just have your utility change out the meter.

[austin]

I have compiled the information on the vibration/hum that I have collected so far from this forum, personal experience and various other sources. So far, I have corrected the problems discovered in steps 1-5. This has helped the situation only a little. The next thing to try will be step 6, unless we decide to just bury the cables and be done with it.

1. The forked receptacles for the electricity meter may be loose. They should be tightened or replaced.

2. The electricity meter may need to be replaced.

3. The circuit breakers in the electrical panel may not be fastened tightly. They should be tightened or replaced. In some cases, it may be less expensive to replace the entire panel than just one circuit breaker.

4. The electrical service pipe that runs down the outside of the house may not be firmly attached to the house. This should be remedied.

5. Other cables, such as telephone or clothes lines, may be attached to the electrical service pipe. These should be relocated.

6. The cables that pass inside the electrical service pipe may be vibrating. The source of the vibration is the magnetic repulsion between the electrical cables. This vibration can be attenuated by attaching the cables firmly together at 4-12 inch (10-30 cm) intervals along their entire length using nylon cable ties. The suggested distance is every 6 inches (15 cm). The distance should not be less than 4 inches so as to not interfere with the natural ventilation along the inside of the pipe (a code requirement).

7. The vibration may amplified by transmission and resonance due to the natural frequency of the house that is close to that of the neutral conductor in the electrical service pipe:

7a. The problem may be due to the manner in which the cable support bracket is attached to the house. It must be solidly attached to the underlying frame of the house using bolts, not screws (a code requirement). The frame to which it is attached, not including the exterior siding, must be at least 1.5 inches thick at all points. The thicker the frame, the better the attenuation.

7b. Rather than attenuating vibration, the house may be behaving as a resonance chamber, effectively amplifying the vibration. Moving the cable support bracket to a more solid location may solve the problem. Modifying the structure of the house itself may also solve the problem, but this would be a major undertaking. Another solution would be to bury the cables.

[HayZee518]

If you can disconnect one end of the cables, impart a twist to the whole cable set so they won't be running parallel to each other, this should eliminate the buzz.

[austin]

The problem arises only when the house draws a lot of current such as when every appliance in the house is on (dryer, oven, all stove tops, etc.). This house is heated with an electric only furnace (electricity is relatively inexpensice here - for now).

This is a great forum. Many thanks to those people who take the time to share their knowledge. I'll add the twist to my list. Eventually, we will fix this problem or the whole house is going to be very sleep deficient.

[HayZee518]

I've been in the electrical business for about 38 years. When high currents go through a wire - you can actually see them jump! Take a look at an electromagnet on a crane lifting scrap metal - when the operator energizes the magnet the cables jump.
In the case of house current which is AC, the AC induces a magnetic field around the conductor which causes it to jump.