Can I use a mains relay on veroboard

[JonathanAnon]

I've developed a small circuit for switching a mains relay (which controls a lamp) on and off under specific conditions. I need to fit the circuit in to a proper enslosure so that I can use it. But I dont have access to any proper PCB making equipment.

Now the stripboard is only good for 1 amp current, so my plan is to solder the relay on to the stripboard which will hold the relay physically in place, then solder the wires of the lamp directly to the load side pins of the relay (i.e. so that the relatively large current goes through the lamp's own 5 amp wire and not through the stripboard conductor). Then I plan to fix the circuit securely inside of the plastic enslosure.

Does this sound okay?

[mariushm]

Re: Can I use a mains relay on veroboard

The width and thickness of the copper traces on the stripboard gives you the current handling capability.
You can make large traces by adding a lot of solder and making wide traces that way.

[SteveNielsen]

Re: Can I use a mains relay on veroboard

What kind of strip board is it? Have a picture of it? If it's a strip board for experimenting and temporary circuits then it won't be suitable for mounting in a box permanently. Blank project PCBs with solder pads and vias are available in different sizes.

[budm]

Re: Can I use a mains relay on veroboard

The relay has terminals for the switch contacts for the load so why don't you solder the wires directly to the terminals that are sticking right out at the bottom of the PCB?

[JonathanAnon]

Re: Can I use a mains relay on veroboard

Yeah budm, that is exactly what I plan to do.. maybe I didnt phrase it clearly. I was just wondering if there was any reason that I hadnt thought of why this would not work or not be safe.

Attached is an image of the stripboard that I normally use. I got it from Maplins, a UK store that has branches here in Ireland. They dont specify the maximum current or different trace sizes/widths.

[stj]

Re: Can I use a mains relay on veroboard

the real issue is the gap between the strips,
you need to remove the copper strips between the used ones to prevent any risk of tracking.

i use stripboard for high voltage a lot, it's pretty simple to peel or grind away atleast one track to each side of the high voltage ones.

as for the current, you can solder a length of heavy copper wire ontop of the track to lift it upto 10A or more.

[JonathanAnon]

Re: Can I use a mains relay on veroboard

the real issue is the gap between the strips, you need to remove the copper strips between the used ones to prevent any risk of tracking.

risk of arcing?

Yeah, now that you mention it I have seen guys solder wire in line with the strip, as well as boost the strip with solder (as was suggested above). Certainly valid options as well.

[budm]

Re: Can I use a mains relay on veroboard

You should also have about 6mm gap/conductor traces between the relay's contact terminals (which is in the hot side of the circuit) and the coil terminals or any circuit in the cold side.

[redwire]

Re: Can I use a mains relay on veroboard

I don't bother putting mains relays on veroboard.
Instead, I flip the relay upside down and glue it down with silicone. Then I just solder wires on the relay's terminals.
I would worry too much about meeting clearances for mains voltages with Veroboard. It's not designed for high-voltage anything.

[JonathanAnon]

Re: Can I use a mains relay on veroboard

I don't bother putting mains relays on veroboard.
Instead, I flip the relay upside down and glue it down with silicone. Then I just solder wires on the relay's terminals. I would worry too much about meeting clearances for mains voltages with Veroboard. It's not designed for high-voltage anything.

I guess what it really boils down to is that if I dont solder the relay in to the veroboard, then I would have to find some other way of fixing it to the inside of the enclosure... like using silicone as redwire does. The control side of the circuit is only 9V 30ma max, so the primary safety concern is that the wires are fixed tightly to the relay and that the relay and wires dont move.

[clearchris]

Re: Can I use a mains relay on veroboard

For switching mains voltage I prefer to use a din mount relay with screw terminals for the load. No worries there.

[stj]

Re: Can I use a mains relay on veroboard

30A is overkill for a lamp though!
the relay will probably draw more current than the lamp.

[clearchris]

Re: Can I use a mains relay on veroboard

30A is overkill for a lamp though!
the relay will probably draw more current than the lamp.

Depends on the kind of lamp.

I like overkill though. Lets me sleep at night when my devices are switching mains.

[redwire]

Re: Can I use a mains relay on veroboard

Another option is to use a solid-state relay, like a cheap Fotek SSR ~$4.00 it has a case, terminals etc., low current drive, although it requires a heatsink at higher currents >5A.

Mechanical relay contacts arc when switching load, which can crash your Arduino or Raspberry Pi due to the EMI, and the relays don't last long or contacts weld closed. I'd add a snubber or cap.

[budm]

Re: Can I use a mains relay on veroboard

In rush current of the lamp due to cold resistance can be as high as 15~16 times of the current flow of the hot resistance of the lamp.