Will this work for switching 110V mini christmas lights on and off safely? - Page 1
Forum section: electronics / projects

author: jarrodhroberson
author_rank: Contributor
timestamp: February 08, 2015, 03:28:28 am
content: I have not been able to find any definitive independent documentation that the relay on this board will not burn my house down.http://www.ebay.com/itm/New-1Channel-5V-Relay-Expansion-Board-Module-High-Level-Triger-for-Arduino-MSYG-/171666166850It uses a SRD-5VDC-SL-C SONGLE which I can only really find any specs on in Chinese.It claims Rated load:10A 250VAC/28VDC,10A 125VAC/28VDC,10A 125VAC/28VDCMy plan is to replace all the timers that my wife puts on the lights on the wreaths that she hangs on the windows every year with a ATtiny/433mhz powered wireless receiver and one of these relays.Will this actual switch US 110VAC safely? I know the lights are no where near 10A.Then I can have one 433mhz transmitter trigger all the lights to go on and off at the same time instead of having to synchronize all these timers on each outlet.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: February 08, 2015, 03:58:33 am
content: The c RU us symbol on the top is a combination CSA & UL recognition mark, so that's a real good sign. What they did on the PCB is a big question though.However, I would say where minilights are concerned, if you put a fuse on the whole thing set nice and low you would be *way* out ahead in the not-burning-your-house-down factor. I mean we get all concerned about clearances and ratings here, but what's really likely with them is to get a good arc going in the wires themselves from damaged insulation.

author: jarrodhroberson
author_rank: Contributor
timestamp: February 08, 2015, 04:24:42 am
content: Thanks for the reply, all the light strands have fuses build into the 110 plug on them now, so that should take care of that.

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 08, 2015, 04:43:41 am
content: They are so cheap it would be worth buying a 5-pack just on speculation. I agree with Mr. Moir that it somewhat depends on how well they designed the PC board unerneath. But I would have high expectations that it would safely handle modest loads like mini-Christmas light strings.

author: jarrodhroberson
author_rank: Contributor
timestamp: February 08, 2015, 04:52:06 am
content: This one has a nice slot designed into it so I think I will get it and try it.

author: eneuro
author_rank: Super Contributor
timestamp: February 09, 2015, 01:01:15 pm
content: Does it has some kind of softstart feature or this switch is too slow?Anyway too many China characters on this board

author: Richard Crowley
author_rank: Super Contributor
timestamp: February 09, 2015, 01:27:21 pm
content: Yes, that example looks reasonably good.My major complaint would be that it has no provision for mechanical mounting (like a couple of screw holes, etc.)Do they think people will just let these things flop around in the breeze, "secured" only by the connected wires?

author: Ian.M
author_rank: Super Contributor
timestamp: February 09, 2015, 01:53:45 pm
content: Its also mechanically weak as the notched out area is approx 1/3 the width of the board.Q. Would I use it for switching an amp or two at 12 or 24 V?A. Probably if I had it handy + some foam VHB tape to mount it.Q. Would I use it for >3A or >50V?A. H**l No. There is absolutely no way to mount it safely short of a custom moulded plastic mounting base.

author: eneuro
author_rank: Super Contributor
timestamp: February 09, 2015, 09:36:34 pm
content: Sometimes it is difficult to buy cheap PCB with good connectors, so I have my own footprint for such much more powerfull connectors 3mm inner diameter and 7mm outer ring secured with spring washer and submerged in non-conductive substance - hot gluedThose connectors looks like those 24VAC transformer inputs below-not submerged yet, ready for testing after soldering this simple prototype +/-12VDC PSU for AC mosfets switch:Of course it require a little effort to make proper wires, but it is better sometimes have something with label"Made at Home""NOT IN CHINA"