What is a Volt-Free Contact? | Electricians Q&A
Volt free, potential free or dry contacts are commonly found on electronic equipment. In this video, we explain what a volt free contact is, how they operate and why you'd use them.
This electricians' Q&A was raised in response to our recent review of the Ferret Wireless switch from RF solutions. 📺 👉 • RF Solutions Ferret - ...
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🕐 TIME STAMPS 🕕
00:00 What are volt free contacts
00:42 Loads of electronics
01:35 No volt contact
01:58 Common
02:31 Normally open and normally closed
03:42 Line and switching line
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Check out the RF Solutions Ferret with volt free contacts ✅ 👉 kzhead.info/sun/rNKBZJqXf4KIhXA/bejne.html
Volt free contacts have been used in PLC and fire alarms for years, it's only recently hit the domestic market, mvhr's and heating controls seem to be becoming this way.. isolated supply is another term... good explanation Joe
Great explanation, I'm currently using a 4Ch Sonoff controller in conjunction with an RF Door Access system I've installed for our garden gate. It enables me to interrupt the Push to Open and/or Maglock circuit in conjunction with smart routines to enable or disable use of the gate at certain times or on certain days and it works really well
Great explanation Joe 👍, we mostly use them in automation functions and time functions, the din rail mounted timers from the likes of greenbrook work in the same way, we use them for timed opening of site gates etc, normally with a gsm or rf/wifi receiver in parallel for out of hours access.
I used to use a volt-free Shelly 1 smart relay to control my garage door opener via my smart home and phone. It was a really old opener and therefore only had a standard RF remote. The Shelly has Wi-Fi so connected to my home network and can be controlled from anywhere. I powered the Shelly with a 12v adapter and used the volt-free relay to connect the push button terminals on the door opener.
I've been asked that question before "what is a volt-free contact". My answer has not changed - "its the arse end of a relay"!
😂
I have been using volt-free/potential-free/dry-contact in my circuits, since 2015. However, I have been using the term ISOLATED for this.
Great vid. Thanks from down under
Well explained Joe 😁
You're a great teacher.
I appreciate that! 👍🏻
Have volt free on my UFH control, it is on a separate electric circuit to the boiler, so has a volt free contact to switch the boiler signal on when demand for heat is there. So no connection across circuits. I wonder if it should have a sticker indicating multiple circuits should be isolated before opening. Or maybe it is no different to the 2 gang switch at the bottom of my stairs. Thanks Joe
I mostly use them in ripple control receivers for photovoltaic installations
How do i wire two ceramic panels controled by a volt free thermostat.?
So we're dose it get the power to close the relay and the control pcb.
Sounds fun but I'm assuming it can't be fitted into an existing installation. Really need one that can take 230V but that means a transformer inside the back box.
They do make a small PSU that could fit in a deep back box, check the full video out: kzhead.info/sun/rNKBZJqXf4KIhXA/bejne.html
Theres a volt free contact on Danfoss roomstat. How do you separate hi / low volts in back box?
Just make sure the lower voltage conductor has insulation rated at the higher voltage. 👍
@@efixx that's what I have done in the past ,also seen a paxolin separator used ,
Her in Denmark we call them potential free contacts.
Good to know. 😊
Same in Germany. Potenzialfreier Kontakt.
Finland too
So dry contact are voltage free contact
Interesting. So another pain in the bum when it comes to doing an IR test ? So we will have to waste time taking that thing out of circuit in order to carry out the tests? Brilliant idea,not but who am I to argue i’am just a Humble spark who’s opinion means nothing. Great video as always Joe 👍
Why do you need to take it out, its like any old light switch, just operated by a remote lol
@@pn8902 because an IR test could damage the electronic circuit board.
@@Dog-whisperer7494 right, but the relay’s outputs are galvanically isolated from the rest of the circuit (trust me I’m an electronic engineer), its just two contacts like a 2 way switch. However it depends on the type and quality of relay used. Besides, what if it was a regular dimmer switch, you’d have to remove it anyway so is it really a big deal.
@@pn8902 I get your point but BS7671 says electronic equipment must be removed from circuit before doing IR test
@@Dog-whisperer7494 You need to think practically. Which IR are you measuring? The power to the device is DC at low voltage and you need to have a power supply to feed it. You're going to be testing the IR of the cable connected to the output. There is no reason why you can't apply the high test voltage with the cable connected to the relay. If the relay has been spec'd correctly it will handle it. You can research the type of relay online from its manufacturer and part number and make a determination as to whether it can handle the voltages in an IR. Or you can try it out. You don't have to blindly follow BS7671: it cannot cater for every single type of electrical apparatus that could be connected in an electrical installation.
Hear we go again . I get in trouble because of someone else’s ignorant disrespect for my dislexic
?
It’s shows the sad state of electrical apprenticeship training that this sort of thing has to be explained! Or is that just from the training providers I see?
This is quite a bad and confusing explanation.
I have been using volt-free/potential-free/dry-contact in my circuits, since 2015. However, I have been using the term ISOLATED for this.