RESIDENCIAL POWER LIMITER
RESIDENCIAL POWER LIMITER
(OP)
Hi, I would like to know if there is a device like a circuit breaker that could be used to limite the power of a household to a selectable value like 10 kW or below and with automatic reset.
I have heard about something call MCB (Mini Circuit Breaker), but I'm not sure if these devices have these capabilities.
Regards.
I have heard about something call MCB (Mini Circuit Breaker), but I'm not sure if these devices have these capabilities.
Regards.






RE: RESIDENCIAL POWER LIMITER
You want to trip a breaker on peak demand? What for? The service drop and Service disconnect/OCP already limit the amount of load a service will carry.
If it's the ability to vary the trip value you are after, then I guess you can buy an electronic or analog breaker with resetable trip values, but that's expensive and only allows you to LOWER the trip setting, but I am not sure what that buys you.
Regards,
EEJaime
RE: RESIDENCIAL POWER LIMITER
RE: RESIDENCIAL POWER LIMITER
RE: RESIDENCIAL POWER LIMITER
Bill
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"Why not the best?"
Jimmy Carter
RE: RESIDENCIAL POWER LIMITER
Yep, some utilities use them in lieu of a service disconnection for unpaid bills. A 93-year man in Michigan froze to death a few days ago because his power was tripped off, apparently.
RE: RESIDENCIAL POWER LIMITER
RE: RESIDENCIAL POWER LIMITER
So, once you sign a contract with the utility and they determine that your demand will be above the 10 kW, then they assign you a rate with demand charge and to ask for a rate change you need to install a power limiter. But the utility doesn't supply this power limiter. Like Jghrist says there are some sophisticated management systems that cost a lot and let you control each independent circuit within a panel board.
Then, I was wondering if I could find a simple device, like a breaker, that allows me to control the maximum demand and let me set the demand value, that would turn everything off at the set point, but with a adjustable time delay to reset. I have to say that I have a backup power source (an inverter), that would supply only part of the load (lights mainly) while I shed some loads to avoid the power limiter to trip again.
Regards.
RE: RESIDENCIAL POWER LIMITER
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Load miser;
The load miser is a switching devise that supplies current to one of these two appliances at a time since there isn't enough current carrying capacity in the 10 gauge wire to operate both appliances simultaneously. Therefore, the load miser gives one of the appliances priority. The load miser cuts off power to the non-preferred appliance when the current flowing through the miser reaches 80% of the upstream fuse or breaker rating.
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Bill
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"Why not the best?"
Jimmy Carter
RE: RESIDENCIAL POWER LIMITER
The Guardian Power Master Load Shedding Device Part# 5239 could be used if there are some loads you know will push demand over 10 kW.
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There are quite a few products on the market that are designed to shed load while running on emergency generators.
RE: RESIDENCIAL POWER LIMITER
Where are you located JAMartinezB?
Keith Cress
kcress - http://www.flaminsystems.com
RE: RESIDENCIAL POWER LIMITER
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RE: RESIDENCIAL POWER LIMITER
I used a couple of old Square D overload relays with bi-metal mechanisms and automatic reset. I wired the output of the small generator through the overloads. At about 80% load they would trip and sound an alarm to give the caretaker time to get the big set started.
Comparing Cadillac solutions with Volkswagon solutions, this would probably come in at about Mountain Bike.
Bill
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"Why not the best?"
Jimmy Carter
RE: RESIDENCIAL POWER LIMITER
I'd think you could install an energy transducer and feed the output to a small PLC. Then, you can program the PLC to activate shunt trips in different circuit breakers to shed load. Shouldn't be too expensive if you are capable of doing some integration and PLC programming.
You could use a Tyco Quadratic Integra 1530 meter cost ~$600 connected via modbus or pulse or analog to a small PLC of some sort.
RE: RESIDENCIAL POWER LIMITER
Use the single pole device to interrupt half (roughly) the 120 V and all 240. The double pole device at 30A will get you closest at 7.2kW.
No reason a current limiting device won't work, since voltage should be reasonably constant (within ANSI).
This is a high price to pay to stay within your rate case. Think of all the clocks to reset, computers, etc.
RE: RESIDENCIAL POWER LIMITER
There are some horror stories about load limiting schemes where a load analysis was not done properly and an attempt was made to limit the load to less than the safe minimum.
Bill
--------------------
"Why not the best?"
Jimmy Carter