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What Bathroom Exhaust fans require a Neutral switched Timer?

12K views 10 replies 4 participants last post by  AandPDan 
#1 ·
So we're putting in 2 bathroom exhaust fans, and I'm replacing the wiring for the whole house fan at the same time. They all need (or I'd like) timer switches on them.

There are plenty of regular count down timers which don't require a neutral wire, and there are a few which have a neutral wire connection on the timer.

The bathroom fans we got are Panasonic Whisper Ceiling fans, 80 and 110 cfm, and the whole house fan is some gigantic 3'x3' that has probably been in the house since it was built in 1953.

Reading reviews on some of these switches, it seems that some fans require a neutral switched timer, and some do not? I'm running all new wiring, so that's not the problem. Specifically I read on Amazon that the Panasonic fans would not work with a non-neutral switched timer, specifically someone said:

"I agree with several of the reviewers here who have noted that this will not work with many newer fans. This does not work with my 80 CFM Panasonic, which is a modern, moderate size fan that draws 25 watts. For best compatibility with any fan, Lutron recommends the MA-T51MN instead."

http://www.amazon.com/Lutron-MA-T51...dp_top_cm_cr_acr_txt?ie=UTF8&showViewpoints=1

So I'm trying to figure out if it's something about the motor that requires a neutral switched timer? I assume the whole house fan (which has a simple twist timer now) isn't neutral switched, but I'm trying to wrap my head around why that won't work for the Panasonic fans. I probably answered my own questions and shouldn't question people's reviews, but I'm also wondering if maybe they just have a bad ground which is interfering with the timer's function too... Thanks
 
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#3 ·
I don't have a problem running a neutral wire to the box, but some of the switches only have 2 hots and a ground, and some people say that this can't control "modern fans" so I'm just trying to understand which switch to buy, as the Neutral switched fans are $50 vs. $20-$30.

But it would be easier to run just one wire and use the neutral leg as a switched leg... but I'm not sure that meets 2008 code which I'm on, and if I need to use a neutral switched timer eventually I guess I should run that extra wire anyways.
 
#9 ·
I don't have a problem running a neutral wire to the box, but some of the switches only have 2 hots and a ground, and some people say that this can't control "modern fans" so I'm just trying to understand which switch to buy, as the Neutral switched fans are $50 vs. $20-$30.
Some timers pass a current through the device to power the timer. With older fans and incandescent lights this isn't a problem. The power is low enough not to affect operation. The newer fans (DC motors) and CFL's do not tolerate any power passing through the device when "off."

The electronic timer may not be a true ON-OFF switch.

But it would be easier to run just one wire and use the neutral leg as a switched leg... but I'm not sure that meets 2008 code which I'm on, and if I need to use a neutral switched timer eventually I guess I should run that extra wire anyways.
Put the extra neutral in, 2011 NEC requires it. It is also NOT a "neutral switched timer" It is a timer that requires a neutral - BIG difference. You can not switch the neutral by Code.
 
#4 ·
I think some of those reviews are lame.
The timer is just a switch.
It switches the hot wire on then off, just like a toggle.
The only reason to have to have a neutral, is the switch would require it.
 
#5 ·
That's kind of my thought, I know to get a good DC reference and presumably power for the DC circuitry you probably need a good ground, and I'm making the assumption that these people don't know how to test for that. I had an electrician put in a new panel and 2 ground rods per code, so I'm pretty confident in my grounding circuit. I'll pick up the non-neutral switched timer and give it a shot, I can always return it to home depot/lowes. I just don't understand why people blame the fan for the switch not working correctly... it's a relay... it should just look like power to the fan.
 
#7 ·
I think I will just in case, no sense in tempting fate. Who knows what else the future might bring. I could get the wife to go for 2x$30 switches, but 2x$50 kinda broke the psychological boundaries of how important a timer switch for bathroom fans are... But yes, all brand new 12 gauge wiring.
 
#10 ·
I prefer the bathroom fans to be "walk in and smack" kind of switches, less chance of people lowering the timer... so for the bathrooms I'll go with the Lutrons probably. For the house fan, I'm not opposed to the mechanical timer, but I think the wife will want a standard decora electronic switch. I'll run a neutral to the box for code purposes.

It looks like Panasonic makes both Condenser (AC) and DC brushless motor models. Their "Whisper Green" are the DC brushless. I didn't get the "Whisper Green" model...

I think you're spot on with the trickle charge through the motors AandPDan.

So let me lay it out and feel free to correct me for other's future reference... you have 3 kinds of switches

Mechanical timers, require no extra electricity, therefore have no need for a neutral. Works with all fans, lights etc...

Electronic timers which do NOT require a neutral. They power themselves through a trickle charge through the motor. DC motors or lights which have electronics like ballasts for fluorescent (or LEDs?) will probably not work with these. Heresay on the internet says some a/c fans do not tolerate this trickle charge through the motor, unknown which models do not support this.

Electronic timers which require a neutral. They change themselves from the incoming power and neutral, and can function more or less like the mechanical switches, as far as compatibility is concerned.
 
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