Hi.
Just wondering if anyone here is using the popular Aeon Labs DSC06106-ZWUS (image attached) to measure power usage of inductive loads such as:
- Air Conditioners
- Fans
- A refrigerator
- A washer
- Or anything else that has a motor
As you may or may not be aware - you should not do this as the device is only rated for resistive loads. And this is the case for most of the Z-Wave switches I've seen. Even those that are sold as "Appliance Switches" are not rated for inductive loads; this is unfortunate and a little deceiving since most appliances are inductive in nature. For example, if you look up this device right now on Amazon it shows that it can be used to monitor a washer (and it says this text is "From the Manfacturer"!!). But it's the rating label of the device (as approved by NEC/CSA/UL, etc) that's important.
Go ahead - try to name a 15A appliance that is resistive (other than a heater)? There probably are a couple, but the majority will not be pure resistive.
Apologies if this opens a can of worms (or a can of worry) for some people.
So is it safe? Officially, no - it's not. Each country has an electrical code (NEC in USA, CSA here in Canada) that specifies rules and using this device for any of the above purposes violates that rule. It's a misuse of a device, and right there in the manual for the device it says Aeon Labs is not liable for damages, etc, due to a misuse. I agree with them on this one, although I do think they suggest that this is safe for inductive loads by calling it an "appliance switch and monitor".
So is it safe - unofficially? Maybe for energy monitoring only. In my opinion, the reason this device is rated for resistive loads only, is because its relay is not rated to interrupt inductive load current. This type of current, by its nature, will cause a small arc across a set of contacts should the contacts open. Eventually this may ruin the device and may have other safety implications. However, if the device is always ON (which is how you may use for an AC or a refrigerator, the contact will always be engaged and there will be no arc.
Disclaimer: This is a theory only. I cannot comment on why such a device is not officially approved for inductive loads. You should always use devices as designated by their manufacturers recommendations (and by NEC/CSA approvals, etc). All of that said, is anyone out there using these devices for energy monitoring of AC units or other motor-based appliances? Personally I'm thinking I might use it anyway (as described above as an energy monitor). Would just like to know if other people have or have not had any issues with using it this way...