Hole Size

[svenedin]

My old electric pump lasted 34 years......I don't use it much because it uses screen wash rather fast and the bottle is very small but it's handy when I can't stop and clean the screen by hand. The pump only needs a live feed from a momentary switch. The earth can be to one of the mounting screws. There needs to be a foot valve (non-return valve) on the end of the tube that goes in the bottle. This is so the pump starts with water in it. It can be damaged by running dry. This is no different from the water-pistol manual pump which also needs a foot valve.

Stephen

[simmitc]

Grommets should have a specification that gives ID, OD and wall thickness. As an example, OD 13mm, ID 6mm (for single tube), wall thickness 1mm would require an 8mm hole and give 3.5mm border around the tube - remember that across the diameter will be two walls, one each side of the hole.

[Bill_qaz]

My old electric pump lasted 34 years......I don't use it much because it uses screen wash rather fast and the bottle is very small but it's handy when I can't stop and clean the screen by hand. The pump only needs a live feed from a momentary switch. The earth can be to one of the mounting screws. There needs to be a foot valve (non-return valve) on the end of the tube that goes in the bottle. This is so the pump starts with water in it. It can be damaged by running dry. This is no different from the water-pistol manual pump which also needs a foot valve. Stephen

Optionally you can put a live fused feed direct to the pump, then run the earth wire to your switch and the other side of the switch to ground. That way your fuse is close to the supply point.
You can also buy washer reservoir with the pump built in, depends what you prefer

[myoldjalopy]

Gentlemen, thank you for your comments, suggestions and pictures. I am now able to make an informed decision on the matter.