UL508 approved wet floor sensor

[Marc]

Any of you guys using an electronic wet floor sensor that is UL listed?

Marc

 

[XtremeIN]

I am not sure if it meets your required specs, but www.Winland.com, makes the WaterBug. We have used them in several aplication without any issues.

Micheal

 

[keithkyll]

Not sure about UL508, but these are the safest sensors I've found. Yamatake makes sensors for chemical processing. This means it uses optical detection to sense any liquid, not just water.

The simple one is HPQ-D. It sells for $148.00.
The other unit is more expensive, but inherently safe. The HPF-D040 is $350.00. It's a fiber optic head. It needs an amplifier. Use HPX-H1 - $85.00.
I'm using this one in a project that has flamable chemicals.

The prices are from EMI Pumps. Website.

 

[Marc]

XtremeIn, we already use the waterbugs and have for years, they work great but they don't have a UL listing so in the UL508 panels we manufacture, we can't use them without jumping through hoops. I'm looking for an alternative, preferably something that will give us a contact closure to a PLC and can be completely outside of the panel.

Keithkyll, I will look into these, they look a little high tech for a wet floor sensor but they do say that they expect UL508 approval by 2002???

Thanks for the responses and I look foreward to anyone else who might come up with some other suggestions.

Strange how the internet has become so populated that a search for "wet floor sensor" or "leak detector" or "Industrial water leak sensor" can result in 385,435 results.

A forum like this can work as a smart search sometimes and we can all give each other feedback on tips and tricks that we have found in the real world... That's pretty cool
Thanks Phil

Marc

 

[keithkyll]

I work in the Semiconductor Industry, so my perspective is a bit different. I've seen the WaterBug style used, as well as the Yamatake. The WaterBug uses electrical contacts feeding an OpAmp. Although we would consider it safe at 24DC, it still has a direct electrical contact to the water on the floor. The lack of isolation may be why it doesn't get UL508 approval?

Optical is the next choice if you don't want to sense it electrically. The Yamatake HPQ-D is typical of the different versions I've seen.
Yes, maybe a little high tech, because it's built for a harsh environment with solvents and acids. There are other manufacturers that make optical and ultrasonic sensors to detect liquid, but the Yamatake is the only one I've found that is designed to sit on the floor (bottom of the cabinet in Semiconductor applications).

Yamatake is a Japanese company. They may have UL508 approval, but just haven't updated the English version of their website yet. Give them a call or email. Tech support in both the US and Japan is good. Japan speaks (writes) English, and responds quickly.

 

[ndzied1]

You might want to take a look at 43.2.1 of the UL508 specification which states,

"Components and wiring located entirely within the low-voltage limited energy circuit are not required to be investigated."
In other words, the inspector doesn't (can't) ding you on these. Essentially what that says is you could put an open knife switch shorting power and ground in a low voltage limited energy (LVLE)circuit and still meet UL508 (not that I would recommend it).

You might need a small isolated power supply for this device to qualify for the LVLE rating but the switch is fine. You'll have to investigate the spec for yourself there.

Remember, there are really only 2 underlying purposed for UL508.

• Prevent Fires
• Prevent Shocks

That's it!. It doesn't care if your panel looks good. It doesn't care if your panel works right. It doesn't care if your panel works at all!!!!! So long as it doesn't present a shock or fire hazzard.

 

[Marc]

Good point Norm,

I'll look into that section again and see what the deal is. I was told that this was pointed out in one of our audits and it was suggested that we pwoer the waterbug through a GFCI to avoid any issues.

Thanks again

Marc

 

[ndzied1]

I forgot the GFCI exception also. That is good for one device.

The reference I gave you came from what I learned in a class that I took at UL on 508. The instructor was very good and made a point to let us know about the Low Voltate Limite Energy exception.

I would recommend a class if you deal with 508. Here is their schedule:
http://www.uluniversity.com/SUTRA/shopul/customer/home.php?&cat=344

<I have no affiliation w/ UL>

 

[dash]

There is a specific wattage that you must stay below for circuits below around 24V. I think that it is around 48 Watts. So as long as the circuit has a 2A fuse on the circuit it will not be required to be industrial UL listed.

Darren

 

[Marc]

Thanks Norm and Darren, I took that class but it was about 4 years ago. I will be attending a UL508 class on SCCR next thursday but maybe I can bug them about details on LVLE circuits.

Marc