Hello, I am Bob...



I live in Sun City Palm Desert - District 4.

This information is specific to my house only... but might apply to your house as well.

I am told that my house was built after all the other ten houses on our street were built and occupied. There are several original owners on our street - they all tell me the same story. However, most of the houses seem to be arranged in a similar manner with respect to the garage and mailbox pillar lighting.

I have assisted many wonderful neighbors in several successful illumination repair and recovery missions! I tell no tales - I affirm the following to be as truthful as humanly possible.

Your house might be arranged differently. I am just trying to point you in the right direction...

bob@infoforyouand.me  

Figure 1 - Typical Photoelectric Switch Location

The west side of my house/garage - a typical configuration for most Sun City Palm Desert homes. The photoelectric switch (sensor, photocell) is located above the service/circuit breaker panel. The sensor is powered by circuit breaker number 4 so, yes, I/most of us do pay the mailbox pillar lamp electricity cost. My sensor is low enough that I can cover it, for testing purposes, without standing on a ladder. I use a section of used bike tire inner tube that has been closed off at one end with electrical tape. Anything that would fit over the end of the sensor and block the entry of light is fine. If you have to work on the sensor for any reason I would suggest opening the breaker and testing the circuit for power.

If you use a piece of opaque tape to test the sensor make sure to clean off the sensor afterwards or it will attract sand/dirt and degrade its sensitivity.

Figure 2 - House to Direct Burial Wiring Junction Box

This is the east side of my house. It is the side that is nearest the mailbox pillar. After the wiring leaves the sensor it probably travels to the garage light and then to this junction box. I say probably because I can not see the wiring. I hope I never have to see it. I do know that the building wire (Romex®) for the mailbox pillar lamp terminates here. At this point it is properly spliced to the direct burial cable. It then begins its underground journey to the mailbox pillar. My house has only two of these handy boxes (4" X 2") with blank covers. One is below the electrical service panel for the grounding electrode connection and this one. Even though I can't see what is going on underground, I would venture to guess that in almost every case if you find the handy box nearest the mailbox pillar and draw a nearly straight line between the two you would be close to locating the direct burial cable path. Remember, if you have a damaged direct burial cable you don't have to remove it you only have to repair or replace it.

This is also a convenient point to do a bit of troubleshooting. If you have 120 volts alternating current at this point but not at the mailbox pillar the only thing between here and there is the direct burial cable.

Figure 3 - Possible Cable Pathway to Mailbox Pillar

From this view you can see the shortest and most convenient path from not only my house but my neighbor's house to the mailbox pillar. His electrical service panel is on the east side of his house and the direct burial cable junction box is on the west side of his house. Our houses were built at different times so they probably do not share a common trench to the mailbox pillar. Adjacent houses built at the same time probably share a single trench and it may follow the property line. Just a guess...

Figure 4 - Cables Entering the Mailbox Pillar

I have no idea what the conduit under the sidewalk looks like but protection must be provided for the cable before it reaches the correct burial depth at both ends.

Figure 5 - Two Cables One Conduit

This is inside the mailbox pillar. You can see the single conduit with both cables entering the space. The conduit appears to be nonmetallic.

Figure 6 - Wiring Is Reversed

The secrets behind those little doors. I have my sensor blocked right now and my garage lamp is on but my neighbor's lamp is on in the mailbox pillar. I see this all the time when I'm riding around on my bike at twilight and lamps are coming on one at a time. Sometimes these mailbox pillars are damaged and have to be removed to be repaired. A perfect situation to cross the cables if the installer is not careful. Always test and verify.

Figure 7 - Properly Identified Cables

I decided to reverse the cables in the mailbox pillar and tag them properly. It is not mandatory that the lamp under your mailbox be energized from your house but sometimes having things as you expect them to be will save time especially when you are troubleshooting. It might help the next person who owns the house. It will be helpful for the technicians who need to remove and replace the pillar if it is ever damaged.

National Electrical Code 2023 - NFPA 70 - Article 110.12 states, "Electrical equipment shall be installed in a professional and skillful manner."

Older code editions were worded differently, "Electrical equipment shall be installed in a neat and workmanlike manner."

Figure 8 - Existing CFL and Socket/Ballast

These fluorescent lamp sockets/ballasts are failing and they are being replaced with LED lamp sockets. This equipment is supplied and installed by the homeowner association.

Figure 9 - New 6 Watts 480 Lumens LED Lamp

A friend of mine and his neighbor were having problems with their mailbox pillar lamps so engineering replaced both fluorescent lamps with a single LED lamp. Only one homeowner supplies the electricity for the single lamp. Who could it be? Figure 14 explains the approximate cost of operating CFLs and LED lamps.

Figure 10 - Explanatory Wiring Diagram

I think my garage and mailbox pillar lamps are wired similar to this diagram. I do know that circuit breaker number four controls the power to this circuit. I make it a point to know which breaker supplies power to every device in my home.

Figure 11 - Circuit Breaker #4

View my entire Circuit Breaker Directory... you will not be disappointed!

Figure 12 - Photoelectric Switch Time Delay

The part of the photoelectric switch you don't normally see when it is installed. The OFF to ON time delay can be as long as 120 seconds with this particular brand of switch. My current switch takes about 100 seconds to turn ON once the sensor is blocked and about 15 seconds to turn OFF once the sensor is uncovered during daylight hours. So if you install a new sensor give it time to change from OFF to ON. I suspect the delay is built into the switch to prevent flickering during dusk or dawn.

Figure 13 - Photoelectric Switch

Usually you only see a small portion of the threaded section of the switch protruding through the handy box cover. The very tip of the switch should be kept relatively clean to function as intended.

Figure 14 - CFLs Electricity Usage and Cost

The calculator used for the above estimations can be found here.

I would suggest dividing the entire amount of the electric bill by the total kWh to find the cost for one kWh.

For example: total amount of bill (138.82) / kWh (789) = 0.1759 ≈ 0.18/kWh

Figure 15 - LED Lamps Electricity Usage and Cost

The calculator used for the above estimations can be found here.

I included this cost analysis because if you did have a damaged direct burial cable you could safely abandon it and parallel the nonworking lamp with your neighbor's working lamp - with their permission, of course. If the cost was .18/kWh, but you rounded up to .20/kWh, and using example B above, the total yearly cost would be $11.39 per 13 watt CFL... less than two dollars a month for both CFLs.

Also, the engineering department seems to be installing a single LED lamp to replace both CFLs when the CFL sockets/ballasts stop functioning properly (See Figure 9). Homeowners will be interested in their monthly cost for these new LED lamps - and they are much less expensive to use. The new LED lamp uses only 6 watts compared to the 13 watt CFL they are replacing. The LED lamps produce 480 lumens. The CFLs produce 800 lumens. Looks like a little less light output.

Figure 16 - Minimum Cover Requirements

A scan from a recent National Electrical Code (NFPA 70). I have no idea what the building inspectors were requiring or accepting at the time of construction.

Figure 17 - Type UF-B Cable with Ground

A little something for the cable nerds... a data sheet.

Problem:
The garage lamp is on but the mailbox pillar lamp is not.

This is what I would do:

1. Cover the photoelectric switch (sensor) to have it change from the OFF to ON state.

2. Make sure the garage lamp is now on.

3. Go to the mailbox pillar and check whether the lamp is on or off.

4. I have a voltage detector pen (as seen below in Figure 18) so I would check for voltage on one of the conductors. If there are two lamps in the pillar I would check all four current carrying conductors. If none of the conductors indicate voltage I would move to the junction box on the side of the house.

5. Open the junction box and check for voltage on one of the conductors. You more than likely will have voltage here unless something is wrong with the wiring in the house. This is not as common a problem as a damaged direct burial cable - but it could happen. Was it something the homeowner did? Ask them. If you're the homeowner ask yourself. Did you do any drilling or cutting into the drywall or stucco? Remember, most of the conductors we are working with are de-energized during the daytime and won't arc and spark or make a sound if you damage them.

Figure 18 - Voltage Detector Pen

This is a nice affordable tool for determining the presence of voltage but not the level... you need a multimeter for that. You also do not need to disconnect any wiring to gather worthwhile information. You do have to remember you are working with a live circuit.

Items to Consider

1. Work safe - disconnect the power if you don't need it on to troubleshoot.

2. Make sure you're working on the correct lamp - the cables could be reversed/crossed.

3. Once you are certain which cable is/should be energized from your house circuit breaker panel identify it for future repair work.

4. Watch out for critters (spiders etc.) in the mailbox pillar (I didn't see any).

5. When you block the photoelectric switch (sensor) give it at least two minutes to change from the OFF to the ON state before you assume something is wrong - remove the blocking device from the sensor when you are finished.

6. Close all junction boxes, the mailbox pillar door and the circuit breaker panel cover when you're finished.

7. Take a break!