Battery Cutoff Switch - what side?

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   Some argue that a battery cut-off switch should go on the positive side and some argue it should go on the negative side. 
Does it really matter?

Poll Question: Which side of the battery did you place a battery cut-off switch?
Poll Choice	Votes	Poll Statistics
Negative Side	1	[20.00%]
Positive Side	4	[80.00%]
This topic is closed, no new votes accepted

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Podster Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 16 Sep 2014 Location: San Antonio Online Status: Offline Posts: 1108	Topic: Battery Cutoff Switch - what side? Posted: 23 Feb 2015 at 12:59pm
	Some argue that a battery cut-off switch should go on the positive side and some argue it should go on the negative side. Does it really matter?
	Cliff & Raelynn Ranger 4.0/178 (1/2 ton 5,800lb tow capacity)

techntrek Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group - pHp Joined: 29 Jul 2009 Location: MD Online Status: Offline Posts: 9059	Posted: 23 Feb 2015 at 5:57pm
	Positive side. One point of reference, NHRA rules state a battery cutoff must be on the positive side of the battery.
	Doug ~ '10 171 (2009-2015) ~ 2008 Salem ~ Pod instruction manual

Outbound Members Profile Send Private Message Find Members Posts Add to Buddy List podders Helping podders - pHp Joined: 19 Nov 2009 Location: Oshawa, Ontario Online Status: Offline Posts: 767	Posted: 23 Feb 2015 at 7:45pm
	Positive side. Yes, I'll concede that the voltages are far too low to ground even a sopping-wet, barefooted child who happened to grab a positive wire coming off a negative-switched 12v battery. But its still good practice to always locate a switch on the positive. There is an argument that when you are disconnecting a battery from a vehicle, you should start with the negative side. If you start with the positive side and should your wrench/screwdriver slip and bridge the positive battery terminal to any part of the grounded frame, you'll short/spark/shock and potentially much worse. If you start with the negative terminal, a wrench/screwdriver slip won't be an issue; and then, when you move to the positive terminal, the frame is no longer connected to the battery and again a wrench/screwdriver slip won't be an issue. But, that argument doesn't hold for a shutoff switch.
	Craig :: 2009 RP171 towed by a 2017 F150

furpod Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group - pHp Joined: 25 Jul 2011 Location: Central KY Online Status: Offline Posts: 6128	Posted: 23 Feb 2015 at 7:47pm
	I don't know 'bout no rules and regulations.. I put mine on the positive side because it was closest..

Tars Tarkas Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 14 Jan 2013 Location: Near Nashville Online Status: Offline Posts: 1446	Posted: 23 Feb 2015 at 9:09pm
	I'm no expert but I did a bit of googling about this and it appears that except for the alternators and some other electronics on some fancy cars like Porsche 911s, an open circuit is an open circuit, so it doesn't matter whether the switch is on the positive or negative side. There are a lot of opinions, some of them pretty strong. They are pretty well split but probably lean toward putting the switch on the positive side. I wasn't convinced either way, but maybe some of those opinions were right. There is no alternator or fancy electronics/computers on the Pod, which to me, makes it even less likely to matter which side the switch is on. I read about the NHRA rules, which obviously don't apply to a travel trailer. One of the best arguments I saw for putting the switch on the positive side is that due to the NHRA rules that's where it's more likely to be expected. That only matters though after an accident with potentially leaking gasoline or a need to kill the engine. And the switch the NHRA is concerned with is one that is mounted on the dash so that it can be reached quickly by a hot rod driver or an emergency worker. On the other side of the fence, some people argue that since electrons flow the negative side of the battery to the positive, it makes sense to cut them off closest to their source. Again, no expert, but I still think an open circuit is an open circuit. There is also a lot of talk about the danger of sparks if you loosen the positive battery clamp first and accidentally touch your wrench to a ground. That seems to be a red herring with regard to a switch. Once the switch is installed there is no wrench in the equation. I haven't installed a switch, so I can't click either choice in the poll, but if I were to install a battery switch I'd be inclined to put it on the plus side. If it was inconvenient there I wouldn't hesitate to put it on the minus side though. As far as I know, all switched 12VDC lights and appliances are switched on the positive side, although they would still turn off even if the switch was on the negative side, for whatever that's worth. Of course that is probably only true when the ground is negative. I used to have a positive ground tractor. TT
	2010 176 FJ Cruiser