hi, I have a 1.5 hp submersible water pump (franklin) and want to buy a generator to power it when the electric goes off. I will be looking for a 3.5kw or slightly larger generator to run this. my question is how do I connect the pump to the generator, just take the cable out of the fuse box and put a plug on it then plug straight into the generator? would I need some sort of breaker between the devices to protect the pump? say like a fused extension cable? I will be moving the generator between houses so would it also be ok to plug say fans or aircon units in this way also. ie straight into generator with a plug? sorry if my question is stupid bit I do not have a clue..........

If the pump is all you're worried about, a 2KVA generator would be sufficient and a lot easier on the pocket book. You will want some way of just plugging into the genset though (versus disconnecting from the breaker). To do that properly, you will need a DPDT switch so that it is only possible for the pump to receive power from one OR the other. You don't need to fuse the cord to the pump. You can plug as much as you want into the genset as long as the combined usage doesn't exceed rating - in which case the circuit breaker on the genset will trip.

Are you looking to just supply the pump via the genset?

Are you looking to just supply the pump via the genset?

the pump would work from the mains electric say for 8 months of the year, then when the electric is on-off I would want the generator as backup, also when not working the pump I plan to take it to the main house and use it for say fans and maybe aircon if possible, but really its just for the pump as we need access to water at all times.

Check the start-up amperage on the pump motor, then size your generator.

http://www.submersibleborepumps.com.au/generator_size_for_pump.html

Edited January 28, 201511 yr by Pacificperson

Useful link there PP.

Confirms the OP's original surmission that something around 3.5kVA would be the ticket.

In answer to the OP's other questions...

Right, all small generators in this class will have regular 3-pin mains sockets for output - meaning that the safest/simplest way to utilize their power is to "plug in".

The challenge is, the OP wants to plug in a pump which by the sounds of it, no longer has a plug end. He also wants to be able to move the generator to another site, where he can plug-in AC's and fans.

The way I'd approach this is, I'd install an additional (small) consumer unit at each site - site #1 only supplying the submersible pump, site #2 supplying the AC and/or fan power circuits. Between the existing consumer unit and the new one, I'd install a "changeover switch" which allows the new CU to either get it's power from mains (via the existing CU), or from a plug which can be run to the genset.

That way, you maintain safety of breakers/RCD's in the new consumer units, and the process of switching from mains to genset is safe.

Maybe Crossy has some ideas or can correct my terminology?

^ +1

You could also install without a changeover switch. Which would mean just plug in to mains, or genset as required.

thankyou, as ever very helpful and useful info provided by the good people who use this site.

If you really plan to haul a 3.5KVA genset from one house to another, you will want to mount it on a tractor. Those boys are heavy.

its got to be lighter then moving the 110 Kubota engine- frame that we have been moving from plot to plot before the electric got put in. Kubota 110kg with no frame and oils inside...