meter selection help - Electrician Talk - Professional Electrical Contractors Forum

Aiken Colon · 11-17-2009, 10:44 AM

Service Masters use a lot of blowers for water restoration work. They put in drying equipment into a home. Some homes have 15 amp and 20 amp breakers. The equipment draws different amps for each type of equipment like 1.8 amps 2.5, 3.5, 4.5, 7, 8, 8.6, 9.4, 10amps. They never know how much more equipment we can put on a circuit until the breakers trip.

What type of meter would you guys recommend so they can stick it in an outlet and measure what is available on the circuit.

Thanks

JJ

chenley · 11-17-2009, 11:15 AM

The most feasible thing to do would be to measure the amperage from the breaker that is supplying the receptacles.

I don't know of anything that you can stick in an outlet to measure the current available on a circuit, only way to tell would be to find the amperage rating of the breaker supplying the circuit.

Aiken Colon · 11-17-2009, 12:54 PM

I was thinking of something as simple as a circuit analyzer like an Ideal 61-165. Or maybe just a clamp amp at the breaker like you are saying.

wptski · 11-18-2009, 07:37 PM

Quote:

Originally Posted by Aiken Colon

I was thinking of something as simple as a circuit analyzer like an Ideal 61-165. Or maybe just a clamp amp at the breaker like you are saying.

Yes, the latest 61-165 has a estimated Load On Line but it has limitations. The following was sent to me by a contact I made at Ideal long before the feature was added.

Instruction for use of Estimated Load on Line
The IDEAL SureTest models 61-164 and 61-165 have now incorporated an Estimated Load on Line (ELL) feature. This function allows the user to quickly obtain a general idea of the total current load drawn on the branch circuit. The proprietary way in which these calculations are made allows the user to plug the unit into an outlet and measure current load on that branch circuit.
Best accuracy can be obtained by becoming familiar with the operation of the load on line test. The distance of the SureTest from the load will affect accuracy. Try to position the SureTest close to the largest load on line.
For best accuracy, power up all loads and make certain they are working at their normal rate of operation, then plug the SureTest into an appropriate
nearby outlet on the same circuit. The Load on Line will be very close to
the actual load. The maximum current measured is held in the small display at the top right hand corner. This value will be held until the Sure Test is removed from the outlet.
While you may do so, the accuracy will suffer if loads are turned on and off during the test period. To quickly confirm a questionable reading, remove the SureTest and reinsert it to recalculate with all loads running.
Due to the proprietary method used to calculate the load, variations in the line and neutral resistance can cause significant variations to the accuracy of the displayed current. Ideally, there should be less than 5% Vd and less than 0.25 Ohms of resistance. In cirical applications, it is recommended that a traditional current clamp such as the Ideal Model 61-746 be used at the panel to obtain a very accurate current measurement.
　
　
ESTIMATED LOAD ON LINE.
The estimated load on line (ELL) is limited to a maximum reading of 15 amps, to best reflect actual conditions on the line as the data is monitored. The Peak Hold display will monitor the load as long as the SureTest is plugged into the outlet. It indicates an estimate of the maximum load on that circuit over time. The calculation is based on the
peak current flowing in the neutral conductor. Neutral current is the
result of powered equipment on the line. The ELL will also help indicate circuits that are overloaded, and those that have a common neutral. This is especially important when the circuit being measured powers single phase switching power supplies, like computers. The third harmonic generated by this equipment is not cancelled, and returns on the neutral, causing overload and heating of the neutral conductor. This is particularly true in 3 phase 4 wire panels, (120/208) where third harmonic is very common. The test allows determination of the remaining capacity of the circuit. It can also help determine whether or not the circuit is dedicated, since a circuit with no load will have very low or zero neutral to ground voltage. Any reading over 1 amp indicates the circuit is very likely not dedicated.
The load on line is strictly an estimate. This is an indirect reading, so there may be significant error in the reported values.

cdnelectrician · 11-18-2009, 08:49 PM

I would plug the blowers or other equipment into kitchen receptacles where possible, if the kitchen will not be in use during the restoration of course. Another option, is to use the washroom or utility receptacles (located near the electrical panel). I wouldn't recommend that they open a panel to take a current reading unless they are electricians which I doubt that they are!

Or, have an electrician make a "spider box" for them which consists of a subpanel mounted on a backboard with some GFCI receptacles. On the other end you could have a stove plug, they could just plug that into the stove receptacle in a home they are working on. Again, all depends on what parts of the house are in use at the time.

Aiken Colon · 11-19-2009, 10:27 AM

Thanks guys. I really thought the 61-165 would do it, but I was not 100% sure. I was trying to keep the guy out of having to buy a 1735 or equal.

The other issue, and cdnelectrician touched on it, these guys are not electricians so it had to be something that would simply plug in.

We have a huge demand for items like this dealing with energy auditors all the time, and AEMC use to make something that simply pluged in to an outlet, and if need be a device, and it would show amp draw as well as overall usage.

JJ