If a meter man removes and replaces the meter without turning off the main breaker will this in turn cause enough transient voltage to damage a circuit board within an oven. The meter man also caused an arch when installing test equipment to test the meter. could the arch have caused the transient volts. how far does transient voltage migrate from said circuit disturbances. the oven is within 50 ft of the meter.
transient voltage caused at meterbase.
- Thread starter csutton
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gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
110421-1849 EDT
What is the difference if you open a circuit by turning of a main breaker vs opening the circuit by pulling the meter? They both are effectively a switch. This is the question you need to ask.
I can conceive of a reason the meter first might be a bad choice. But what is your analysis.
If I were doing it I would turn off individual breakers first, and the very first ones would be those with sensitive loads. Then the main breaker, then the meter. In reality on my own system I would probably just pull the main breaker first.
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What is the difference if you open a circuit by turning of a main breaker vs opening the circuit by pulling the meter? They both are effectively a switch. This is the question you need to ask.
I can conceive of a reason the meter first might be a bad choice. But what is your analysis.
If I were doing it I would turn off individual breakers first, and the very first ones would be those with sensitive loads. Then the main breaker, then the meter. In reality on my own system I would probably just pull the main breaker first.
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need good research material
need good research material
I've done a small amount of research and I'm finding that voltage spikes can occur and migrate through the circuit. These spikes can be caused by motors, and other loads. Here is what cherrylandelectric.com had to say,"In reality, as much as 80% of today's electrical problems can be
traced to the activities of such harmless devices as elevators, air conditioners, vending
machines, copiers, and large computers. In fact, even something as simple as turning
lights on and off will cause surges of power and transient voltages."
So what is the difference put the meter in or switching the main. I could imagine archs could happen in both scenarios however if the main is arching there's probably something wrong with the breaker. At any rate arching due to current draw causes damaging voltage according to the article quoted earlier. I guess in this is why you would turn off branch circuit breakers as you described earlier. I guess if the circumstances line up just right and someone manhandles the meter while working on it hot and under load transient volts could be created an therefore cause damage. I would like to see the math behind this scenario though.
need good research material
I've done a small amount of research and I'm finding that voltage spikes can occur and migrate through the circuit. These spikes can be caused by motors, and other loads. Here is what cherrylandelectric.com had to say,"In reality, as much as 80% of today's electrical problems can be
traced to the activities of such harmless devices as elevators, air conditioners, vending
machines, copiers, and large computers. In fact, even something as simple as turning
lights on and off will cause surges of power and transient voltages."
So what is the difference put the meter in or switching the main. I could imagine archs could happen in both scenarios however if the main is arching there's probably something wrong with the breaker. At any rate arching due to current draw causes damaging voltage according to the article quoted earlier. I guess in this is why you would turn off branch circuit breakers as you described earlier. I guess if the circumstances line up just right and someone manhandles the meter while working on it hot and under load transient volts could be created an therefore cause damage. I would like to see the math behind this scenario though.
brian john
Senior Member
- Location
- Leesburg, VA
CS you are correct to some extent, BUT read gar's response, how would the meter man done it any differently. As far as the Arc goes how big an arc like the draw of his test equipment which should be minimal or a arc related to a fault from improper connections at the meter?
Gar's response says (partially) pulling the meter is the same (basicallly) as opening a main under load.
Do not jump to conclusions from a bit of information you have gotten from the web. Research the issue, especially before you talk to the customer.
Gar's response says (partially) pulling the meter is the same (basicallly) as opening a main under load.
Do not jump to conclusions from a bit of information you have gotten from the web. Research the issue, especially before you talk to the customer.
That is it, the customer said they saw an arch when the Meter man installed test equipment. Now was this an fault to ground or a current draw arch? and in each case why does this cause an instantaneous voltage spike that migrates 50 to 100 feet and causes arching in an oven circuitboard. in the case of a ground fault does this travel down the ground path and a current draw does this travel down the hot? I can understand a lightning strike where as you're adding voltage to the system . but how does an arc or fault to ground add voltage to a system and how does that look mathematically ?I guess I'm going to have to dust off my physics book.
anyways I follow you, metermen take meters out and put meters in all the time especially at apartments without turning off the main. there's a lotta questions and you're right the internet information has been limited
so far. thank you for entertaining my conundrum though and I appreciate all the responses . Know of any good sources an this topic?
anyways I follow you, metermen take meters out and put meters in all the time especially at apartments without turning off the main. there's a lotta questions and you're right the internet information has been limited
so far. thank you for entertaining my conundrum though and I appreciate all the responses . Know of any good sources an this topic?
brian john
Senior Member
- Location
- Leesburg, VA
It is always interesting to know why. But in this case I think the HO is on the books for paying for the card.
gar
Senior Member
- Location
- Ann Arbor, Michigan
- Occupation
- EE
110421-2023 EDT
csutton:
Search the Internet for equations that describe what happens when you have a series circuit consisting of a battery, a switch, resistor, and an inductor all in series. Note: any circuit has inductance. The only difference between different circuits is magnitude of the inductance.
Find out what happens in the circuit at switch closure, and at switch opening. Can you instantaneously change the current thru an inductor?
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csutton:
Search the Internet for equations that describe what happens when you have a series circuit consisting of a battery, a switch, resistor, and an inductor all in series. Note: any circuit has inductance. The only difference between different circuits is magnitude of the inductance.
Find out what happens in the circuit at switch closure, and at switch opening. Can you instantaneously change the current thru an inductor?
.
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