Lost Your Noodle...? - 10/07/02 04:29 PM
Good Morning All. Had a rather unusual experience yesterday afternoon at a church bazaar held in a nearly 100 year old community hall where I was providing a sound system. About 1/3 of the way through this, we began having an electrical "event". Some of the lights in the hall suddenly became about 20% brighter, some dimmed, some went out altogether, a few burned out from an obvious overvoltage condition, and the sound system amplifier voltage dropped enough that it started distorting severely. Some of the air conditioning motors (air handlers and condenser units) started humming loudly and every grounded metal enclosure (supposedly grounded...) became energized.
Realizing that we probably had a serious problem with the main service entrance equipment outside, we went to check. There we found that the grounding conductor at the weatherheads (there are two raceways that enter a 400a. main disco) had separated from the POCO conductor. As services go, this is a fairly old one - about 30+ years old. The main disco is nippled into a wire gutter about 7 feet long, with more discos than carter's got liver pills (due to numerous additions over the years). Wiring in this building is a really unique mix - old K & T dating back to the original construction, some wiring done well within code guidelines by experienced professionals, other wiring very poorly done in the worst DIY manner possible (no AHJ in this area, so anything goes, I guess).
I would not want to speculate about whether the grounding conductor opened because of a fault in the system or due to old age. In any event, an electrician (I assume) laddered the side of the building and, once the main disco was shut off, reconnected the neutral. The power was turned back on again, the lights and air conditioning equipment was checked to be sure that things were in working order, and the bazaar continued without incident for the rest of the day.
It appears to me that this building is in desperate need of a rewiring, or at least a service upgrade. The wiring has been "added onto" so many times, I don't think there is anyone who can vouch for the integrity of the system. The fact that the metal enclosures of outlet boxes, breaker panels, etc. became energized during this "event" probably has me worried more than anything else because the EGC, wherever it is, doesn't seem to be adequate.
The people who own this building are friends of mine, and need to understand that this was truly a dangerous situation.
What be your thoughts?
Mike (mamills)
Realizing that we probably had a serious problem with the main service entrance equipment outside, we went to check. There we found that the grounding conductor at the weatherheads (there are two raceways that enter a 400a. main disco) had separated from the POCO conductor. As services go, this is a fairly old one - about 30+ years old. The main disco is nippled into a wire gutter about 7 feet long, with more discos than carter's got liver pills (due to numerous additions over the years). Wiring in this building is a really unique mix - old K & T dating back to the original construction, some wiring done well within code guidelines by experienced professionals, other wiring very poorly done in the worst DIY manner possible (no AHJ in this area, so anything goes, I guess).
I would not want to speculate about whether the grounding conductor opened because of a fault in the system or due to old age. In any event, an electrician (I assume) laddered the side of the building and, once the main disco was shut off, reconnected the neutral. The power was turned back on again, the lights and air conditioning equipment was checked to be sure that things were in working order, and the bazaar continued without incident for the rest of the day.
It appears to me that this building is in desperate need of a rewiring, or at least a service upgrade. The wiring has been "added onto" so many times, I don't think there is anyone who can vouch for the integrity of the system. The fact that the metal enclosures of outlet boxes, breaker panels, etc. became energized during this "event" probably has me worried more than anything else because the EGC, wherever it is, doesn't seem to be adequate.
The people who own this building are friends of mine, and need to understand that this was truly a dangerous situation.
What be your thoughts?
Mike (mamills)