Proper way to join AC-neutral wires in side electronics device - Page 1
Forum section: electronics / projects

author: nixfu
author_rank: Unknown
timestamp: July 23, 2015, 03:37:12 am
content: I am adding an additional AC Switch inside my cheap china made 858-style(see ebay) hot air reflow station. The only "real" AC switch is in the back, and reaching around to turn it off near a hot air gun nozzle is not fun. If it is not switched off via AC, then it goes into standby and I just don't trust it.So, I was going to add an additional AC switch on the front of the top panel and daisy chain it off the read switch on the IEC plug.Here is my basic plan:IEC PLUG --- IEC SWITCH neutral --- LOAD DEVICEIEC PLUG --- IEC SWITCH hot --- second switch AC IN---second switch AC OUT---- LOAD DEVICEBUT, I wanted to use an lighted indicator switch, and that requires the third terminal which is the ground for the ac indicator light to also be connected to ground (neutral).However, the IEC switch only has two one neutral blade terminal and I need to connect both the load and the lamp to that terminal. Right now the load device AC wires are crimped to blade connectors.What would be the proper way to connect both of those wires to a single blade terminal. Can I join them inside the device somehow, and then use a third common wire to connect to the neutral blade terminal on the IEC?Sure I could just do some manual connecting of 3 wires, solder them together or something and be done with it. But I am curious what the proper way to do it would be.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 23, 2015, 03:48:10 am
content: Do you have room to use a piggyback crimp terminal?Like this:http://www.digikey.ca/product-detail/en/MVU18-250DMFK-A/920084-03-ND/1952091A not-so-great-but-works method would be to use a terminal for twice the copper area than your wires, and put two wires into one terminal.

author: nixfu
author_rank: Unknown
timestamp: July 23, 2015, 03:50:33 am
content: I was just looking at some piggy back terminals like those. That might be a possibility. However since it is 120V AC I would probably need to find something fullry insulated/shrouded like the existing ones.That would be easier than the only other solution I thought of which was using a terminal block inside the device.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 23, 2015, 03:53:11 am
content: I like to go for finger safe in panels that can be easily opened, but I don't think it's too necessary for this situation?EDIT: Oh, is this exposed? No that won't do then. I wouldn't even use the insulated ones exposed.

author: nixfu
author_rank: Unknown
timestamp: July 23, 2015, 03:56:22 am
content: No you are correct, there are inside on the inside of the back panel, they connect basically on the back of the IEC connector. So it would probably be ok for the neutral to be unshielded, since the hot wire blade terminal right next to it is fully insulated. I could always put some heat shrink over it I guess as well.

author: Paul Moir
author_rank: Frequent Contributor
timestamp: July 23, 2015, 04:09:21 am
content: Well, if you are buying them just for this occasion, I know you can get the fully sheilded ones as well.http://www.digikey.ca/product-detail/en/0190130030/WM6909CT-ND/3044912Pricey sucker though, even for digikey.

author: DenzilPenberthy
author_rank: Frequent Contributor
timestamp: July 23, 2015, 11:11:32 am
content: I've started using Wago connectors for this sort of thing. For ages now I've been wanting something that's like a 'chock-block' but with the terminals commoned together. These have become my new favourite thing!http://uk.rs-online.com/web/p/non-fused-terminal-blocks/5077011/Lift up the little orange levers, put your wires in then flick the levers back down. They do 2, 3 or 5way versions. I'd use bootlace ferrules as well if you're using stranded wire.

author: SeanB
author_rank: Super Contributor
timestamp: July 23, 2015, 05:38:50 pm
content: You do get double pole illuminated switches that fit the standard cutout. That way you switch both line and neutral, which is safer as you never know if you might have a miswired socket, or are in a country with no socket polarity.