Lightning strike damage to flow meter
Lightning strike damage to flow meter
(OP)
Hopefully this is the right forum-I have a client (municipal) who serves domestic water to an established appartment complex. I was called to look at a magnetic flow transmitter, installed eight yrs. ago, within the complex with regard to continual lightning damage of the flowmeter electronics, according to the city electrician 1 or 2 times a yr over the last 3-4 yrs.
The meter is located in an underground vault, pvc pipe outside the vault, cast iron within the vault. The water line runs adjacent to a road running thru the complex. The electroncs for the meter are in a polycarbonate box 6' above grade. A 20a 120v ciruit is fed from a building on the other side of the street underground to the enclosure.
Examining a couple of "fried" circuit boards (their mounted mounted above grade), the damage is near the connector that feeds low v D.C. to the coils on the meter, not near, circuit wise, to the 120v input to the board. Also damage to the terminal strip at the underground portion of the meter.
I'm wondering now if the damage may not be entering from the utility power- could it somehow be propagating from the vault? There is no 120v power at the uderground portion of the meter.
The surroundings of the above-grade electroncs seemed tame enough- an 8 foot or so berm behind the installation and a couple of 15 foot or so trees within 20 feet.
The meter is located in an underground vault, pvc pipe outside the vault, cast iron within the vault. The water line runs adjacent to a road running thru the complex. The electroncs for the meter are in a polycarbonate box 6' above grade. A 20a 120v ciruit is fed from a building on the other side of the street underground to the enclosure.
Examining a couple of "fried" circuit boards (their mounted mounted above grade), the damage is near the connector that feeds low v D.C. to the coils on the meter, not near, circuit wise, to the 120v input to the board. Also damage to the terminal strip at the underground portion of the meter.
I'm wondering now if the damage may not be entering from the utility power- could it somehow be propagating from the vault? There is no 120v power at the uderground portion of the meter.
The surroundings of the above-grade electroncs seemed tame enough- an 8 foot or so berm behind the installation and a couple of 15 foot or so trees within 20 feet.






RE: Lightning strike damage to flow meter
Mike Halloran
Pembroke Pines, FL, USA
RE: Lightning strike damage to flow meter
It may very well be that the surge is entering from the top, but looking at the meter and board, it's surprising that the surge arrestor, MOV's on the board etc haven't ever been damaged, yet there is terminal strip damage in the vault and circuit damage not near the 120v input. The meter still functions, just the electronics that they're relacing. Lighting does crazy things.
RE: Lightning strike damage to flow meter
Regards
Marmite
RE: Lightning strike damage to flow meter
RE: Lightning strike damage to flow meter
RE: Lightning strike damage to flow meter
When you say a potential difference, are you refering to a potetial present not associated with lightning? The damage indicates a substantial energy surge- some components near the connector going to the meter blown off.
RE: Lightning strike damage to flow meter