Solid State Relays SSRs, anybody use them for HEAVY Loads?

[Industrial Toys]

It's a pain with those heavy wires to remove them from the breaker and bypass it.

Curious how a Hot tub CGFI with the neutral works.

 

[techman]

SSRs will be good for your hot tub. At that current they will likely need a heat sink of some sort. Something like:
Opto22 - 48D25-12 - 48 VAC, 25 Amp, DC Control Solid State Relay (SSR), Transient Proof
Make sure you get one with sufficient voltage headroom for power surges, likely 400 volts or higher. For the compressor the inrush will make it hard to find an SSR with the ratings that will last.

paul

 

[grsthegreat]

I use LoadSheddingControllers load shedding products. They might work for your needs. Very reliable products....up to 100 amps.

 

[the old grind]

My neighbor leaves a valve open (that I added to ameliorate leak-downs) and main switch 'on' for his 6 hp 80 gal 2-stage compressor. It'll cycle every 40 min or so for a whole weekend, and he just ignores it. (out of sight out of mind). Small wonder he has to re-tighten the compressor's head bolts 2-3 times/yr. (no torque spec or pattern needed to do that 'good enough' .. )

How many times do I imagine that WGB just needs a timer-switch? IMO it rarely takes half an hour to forget to turn off something that's rarely used and sucks power when ignored.

 

[CobyRupert]

I like that idea of tripping out the GFI with the Load shedding signal. Easy to do.

Amazing how much leakage current the CGFI needs to trip. Tried 1 meg, nope, 470K nope, then did some googling and calculating. Was amazed I had to go down to 2.2K. And that is how I will shut off the hot tub for load shedding, provided I don't have more nuisance tripping.

Wait, what?

You're going to use a relay to short line to ground (or neutral) to trip out the GFI as part of a load shedding scheme?
Maybe on second reading you're "shorting" through a 2.2k ohm resistor? Is that line to line or line to ground?

Something just seems inherently sketchy about "shorting a GFCI to be a relay" that, although that's sort of what the "Test" feature on a GFCI does.

If line (120V) to ground through a 2.2kOhm resistor, isn't that like 54 milliamps to ground? This seems like a lot given that GFCI's should trip out in the 3-5mA range, but a GFEP (Ground Fault Equipment Protector) trips out in the 30mA range, so you may be on target if you have a GFEP instead of a GFCI.

On my hot tub, the local disconnect switch (as required by code) is a GFCI (or GFEP?) breaker in a fiberglass enclosure, that's feed from a standard type 2 pole breaker in the panel-board.

If I wanted to load shed, I would simply change out the breaker in my panel-board with a shunt-trip breaker that triggers off the load shed signal. This eliminates any relay, but requires a manual reset to turn back on. Requires a space "space" next to the 2 pole breaker in the panel-board for the shunt coil attachment.

BTW: What's so bad about having a coil energized?

 

[Industrial Toys]

Thanks. I have so many projects on my plate and can't afford to just go out and buy a load shedding system. The security RF equipment I am using has really impressed me, although I am not a fan of wireless, for the most part junk.

I do believe you are correct Coby, I got a zero in the wrong place. I admit, it doesn't conform to any accepted manner of doing things, but I actually see little difference in shutting the hot tob off with that breaker, or pressing the test button which is easier and makes for a periodic test, OR tripping it out with a relay. It is actually a really good test as well.

As far as not having a coil running. I have so many systems and buildings, I am conscious of the accumulated 24/7 consumption, all these systems represent. People on here have scoffed at that. but to each his own I guess. I feel sick, if I realize I have left the lights burning in the barn overnight, or some such thing.

What is a shunt type breaker? My HT is about fifty feet from the house Fed from a panel in the wood shed with a FP CGFI. I guess the twistlock at the hot tub counts as a local disconnect.

 

[CobyRupert]

It's a breaker with a "shunt trip" coil on it that opens the breaker when coil gets a signal to do so.
It's a one-way operation. You have to manually reset the breaker.

From what I see, the coil module that's added to the side of the breaker occupies a space in the panel that another single pole breaker would otherwise use. (So a 2 pole shunt trip breaker would occupy the SPACE of 3 poles)

 

[Industrial Toys]

Thanks. I am going to my surplus electrical dealer any day so I will put that on my list.

I knew I had seen one. A friend is in the elect dist bus and I am always getting weird stuff when they do inventory and throw stuff out.

It's a square D, DIN RAIL, 15 amp unit but I can't figure it out or what is written on it. It says SHUNT TRIP, but seems like it's just an AUX or pilot type contact. I know it's too small, but I'm curious about them now.

 

[CobyRupert]

....or just wire circuit through the ‘normally closed’ contact of a regular electro-mechanical relay, and coil only energizes from the load shed signal and contact opens.
Normally coil will be unenergized and circuit continuous.

 

[Industrial Toys]

I looked at that shunt breaker. Yes, it does a you say. What would that normally be used for?. Very ambiguous wording on the unit.

The load shed signal is only momentary. A VERY small miniature relay.