Recommended Sensor for Outdoor Electrical Shutoff Box

[johngalt]

Greetings-
 
Next to my electric meter I have a box that I can open and shutoff the power to the entire house.  It looks a lot like the meter and box in the attached picture.
 
Any recommendations for a sensor to notify me if it is opened?
 

• It is a thick metal box.  Will a normal magnetic window/door sensor work?  Or would a tilt sensor be better?
• I don't want to put low voltage wiring in here for obvious reasons so I want a wireless sensor.  I have an Elk with receivers for both the Elk two way products as well as the honeywell 5800 line.
• Do you think I need an exterior rated sensor?
• Concerns with the metal box and RF transmission?

Thanks!

 

[RAL]

No pictures in your post.
 
A magnetic contact will have trouble working with a metal enclosure, unless you isolate the contact and magnet from the surrounding metal.
 
A better solution would be a tamper switch.  I don't know of any wireless ones, but you could combine it with a wireless window sensor that has auxiliary terminals for an additional wired contact, like the GE NX-650 or the GE/Interlogix 60-362N-10-319.5.
 
But I don't give a wireless transmitter much of a chance of working from inside a metal enclosure.
 
If the sensor is inside the enclosure and is protected from weather, it should be ok.  With a wireless sensor, my main concern would be whether it is rated for the temperature range in your area, especially in winter.  The NX-650 is only spec'd down to 32 degrees F.

 

[johngalt]

No pictures in your post.
 
A magnetic contact will have trouble working with a metal enclosure, unless you isolate the contact and magnet from the surrounding metal.
 
A better solution would be a tamper switch.  I don't know of any wireless ones, but you could combine it with a wireless window sensor that has auxiliary terminals for an additional wired contact, like the GE NX-650 or the GE/Interlogix 60-362N-10-319.5.
 
But I don't give a wireless transmitter much of a chance of working from inside a metal enclosure.
 
If the sensor is inside the enclosure and is protected from weather, it should be ok.  With a wireless sensor, my main concern would be whether it is rated for the temperature range in your area, especially in winter.  The NX-650 is only spec'd down to 32 degrees F.

Thanks for the fast reply!
 
I edited my post and attached the picture I intended to attach originally.
 
I have an Elk 6022 which allows me to wire up an additional sensor.  it is rated for  14 to 104 degrees F so I should be good from that aspect.  I will see if it fits and if I am able to get a signal while it is encased in metal.

 

[lanbrown]

Wireless in a metal box is pretty much a no go.  Almost everyone has someone on the side of the house like that....I just put a lock on it and call it good.  Is the latch just a piece of metal with an eyelet?  You could use a lock to secure it.

 

[ano]

You can put wireless sensors outside the box. I've been using them on outside gates for 8+ years and never had one fail yet. Just add a little silicon sealer.

 

[johngalt]

Wireless in a metal box is pretty much a no go.  Almost everyone has someone on the side of the house like that....I just put a lock on it and call it good.  Is the latch just a piece of metal with an eyelet?  You could use a lock to secure it.

I could easily look it.  In fact I assume that is what the eyelet is designed for.  However, I like the idea of being able to quickly shut off power to the house in case of an emergency.  I could use a combination lock, but I travel a lot and want it to be easy for my wife or someone else to shutoff the power just in case.
 
I clearly get the fact that I want to have my cake and eat it too in this case.
 
I just tried the Elk-6022 in the box and it fits and appears to be sending a signal fine.  I will give it a few days.  The receiver is fortunately just 15 feet away from the box, so hopefully it works.

 

[johngalt]

You can put wireless sensors outside the box. I've been using them on outside gates for 8+ years and never had one fail yet. Just add a little silicon sealer.

Good point.  I have the Honeywell exterior door sensors and I use them for my gate and shed and they work great.  Might be a little big in this case, but even a wireless sensor on the outside of the box might help.  And sure someone could tamper with it, but I will know pretty quickly if my power goes out.
 
I just want to know if the power is out to just my house or multiple houses. 

 

[mikefamig]

Thinking outside the box - would it be good enough to monitor the mains power rather than the box lid?
 
Mike.

 

[johngalt]

Thinking outside the box - would it be good enough to monitor the mains power rather than the box lid?
 
Mike.

Nice pun.
 
When you say mains power are you referring to the any AC outlet in the house?  Or are you referring to the power line coming into the house?  My Elk will alert me when the power goes out in the house.  However, I like the idea of monitoring if there is a voltage detected in the lines coming into my house.  This would also alert me when the power is restored after a big storm and I am switched over to using my generator.  Which is a more practical use case.
 
Does anyone know of a non contact voltage sensor to interface with an alarm system?

 

[mikefamig]

Nice pun.
 
When you say mains power are you referring to the any AC outlet in the house?  Or are you referring to the power line coming into the house?  My Elk will alert me when the power goes out in the house.  However, I like the idea of monitoring if there is a voltage detected in the lines coming into my house.  This would also alert me when the power is restored after a big storm and I am switched over to using my generator.  Which is a more practical use case.
 
Does anyone know of a non contact voltage sensor to interface with an alarm system?

I was thinking of an inductive clamp on the main lines where they enter the main circuit breaker box inside the house but I suppose it could be done inside of that switch box.
 
Mike.

 

[RAL]

Does anyone know of a non contact voltage sensor to interface with an alarm system?

If you have the whole house running on the generator, you can't use a current transformer to detect the restoration of utility power, since the CT detects current flow from a load.  If you have a subpanel style transfer switch, then a CT could detect the return of utility power if you install it on something in the main panel that you know will reliably draw power.
 
Reliance makes an AC field detector that can detect utility power without any load.  It's not designed to connect to an alarm system, but I imagine it could be modified if you have some electronics skills.
 
https://www.amazon.com/dp/B003KREORA

 

[mikefamig]

If you have the whole house running on the generator, you can't use a current transformer to detect the restoration of utility power, since the CT detects current flow from a load.  If you have a subpanel style transfer switch, then a CT could detect the return of utility power if you install it on something in the main panel that you know will reliably draw power.
 
Reliance makes an AC field detector that can detect utility power without any load.  It's not designed to connect to an alarm system, but I imagine it could be modified if you have some electronics skills.
 
https://www.amazon.com/dp/B003KREORA

Maybe add a breaker that puts a small load on the main service that is not routed through the generator?
 
Mike.

 

[johngalt]

Maybe add a breaker that puts a small load on the main service that is not routed through the generator?
 
Mike.

Thanks for the ideas.
 
I have an interlock so when my generator is switched on the main will have zero current on it since the main breaker in my box has to be off to have my generator on. 
 
That AC field detector from Reliance looks really interesting.  I could probably modify it to work.  I saw a review that said that they extended the sensor cable with a RG-59 stranded coaxial cable which could be handy so I could mount it inside.

 

[johngalt]

Just an update.
 
I shoved a Elk 6022 sensor I had around and had two wires connected to it and was able to close the electrical box.  I enabled a walk test and then shorted the two wires back and forth and I was getting levels 8 and 9 announced.  I was surprised, but the signal seemed to be working very well despite being in a metal box.  Clearly it is not recommended to have a RF sensor in a metal box, but it seems to work just fine.
 
The magnet sensor also seems to be working as well.  I stuck the sensor on with some 3M tape and am going to monitor it for a few weeks to make sure I don't have any signal drop outs, false alarms, etc.
 
I still hope to add the AC field detector at a later date.  However, just wanted to add a data point that an Elk 6022 (Wireless magnetic door sensor) appears to work fine in a metal box despite it not being best practice.

 

[RAL]

Just an update.
 
I shoved a Elk 6022 sensor I had around and had two wires connected to it and was able to close the electrical box.  I enabled a walk test and then shorted the two wires back and forth and I was getting levels 8 and 9 announced.  I was surprised, but the signal seemed to be working very well despite being in a metal box.  Clearly it is not recommended to have a RF sensor in a metal box, but it seems to work just fine.
 
The magnet sensor also seems to be working as well.  I stuck the sensor on with some 3M tape and am going to monitor it for a few weeks to make sure I don't have any signal drop outs, false alarms, etc.
 
I still hope to add the AC field detector at a later date.  However, just wanted to add a data point that an Elk 6022 (Wireless magnetic door sensor) appears to work fine in a metal box despite it not being best practice.

Thanks for the update.  My guess is that the flip-up cover of the box allows enough RF leakage that a signal is able to get out.  That, coupled with the short distance to your receiver is giving you a workable solution.