When is local disconnect switch required?

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Old 01-31-16, 09:14 PM
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When is local disconnect switch required?

Reading recent question about garage heater installation and answer to it stating local disconnect switch is required got me a little confused.

I know that the code says means of disconnect or breaker lockout is required for equipment that is not in direct line of sight from the breaker panel.
I see that disconnect switches are used on air conditioner and water heaters all the time.

However, I never seen them on baseboard heater, dishwasher, and radiant floor heater. All of those are hardwired.
Also, I have never seen garage ceiling or wall mounted heater with disconnect switch (unless thermostat on the wall counts as disconnect switch).

Could help me clarify when disconnect switch is required and exceptions?

Thanks.
 
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Old 01-31-16, 09:41 PM
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Line voltage 4-wire thermostat can qualify as a disconnect if it has a marked "off" position.

Hard wire dishwasher needs a wall switch or other disconnect.

In the end it is up to the local authority as to what is required and the inspectors as to what you can get away with.
 
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Old 01-31-16, 09:44 PM
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They are now required on dishwashers. Either a plug and receptacle or a shut-off switch. With my last two dishwasher installs..... the inspectors required a disconnect switch at the dishwasher and a breaker lock at the panel.

This is a confusing area of article 424 that deals with heaters.

It appears according to this code change in 2011 that any heater with a fan requires a disconnect. That would exclude permanent baseboard heating.

Another detail to note....
The motors for fixed electric space-heaters are now considered a continuous load [424.3(B)]. Thus, size the branch circuit at 125%.

Some additional info here from Mike Holt. Article 424: Fixed Electric Space Heating
 
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Old 02-01-16, 07:36 AM
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Dishwashers used to have a mechanical "OFF" position on the selector knob which could be considered a disconnect. The new electronic ones do not have mechanical switches so a cord and plug or disconnect switch is now required.

I always assumed the code didn't require disconnects on resistive heaters because there is no scheduled maintenance to do on them. Equipment with motors needs regular cleaning / oiling / replacement of belts and so forth, thus the additional safety disco needed for a serviceman.
 
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Old 02-01-16, 02:42 PM
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Line voltage 4-wire thermostat can qualify as a disconnect if it has a marked "off" position.
Thermostat is often mounted to the baseboard heater itself and thermostat is pretty much only serviceable part. It is funny how thermostat can qualify as disconnect.

It appears according to this code change in 2011 that any heater with a fan requires a disconnect.
I guess that is because fan needs service?

Dishwashers used to have a mechanical "OFF" position on the selector knob which could be considered a disconnect.
This seems another funny code. Mechanical switch on dishwasher is mounted on control panel and even with switch at off position, I'd say it is quiet dangerous to service as it has live wires inside.

I'm in Fairfax County, VA, and if I remember correctly, they are following NEC 2011 now. I wonder if new installations now have plug or disconnect switch. I'm currently working as cabinet install sub-contractor for apartment renovation in DC. Apartment units are splitted to make smaller units, and electrical contractor pulled new wires to entire unit. But there is no disconnect switch or plug for dishwasher. What is even strange is electric oven outlet is 3 prong instead of 4 prong.
They did use AFCI for bedroom and temper resistant outlets. DC must be at least using NEC 2008.
They did pull permit, but don't know if they are ever getting this inspected. If they do, I'm sure it will fail.
 
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Old 02-01-16, 06:57 PM
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They did pull permit, but don't know if they are ever getting this inspected. If they do, I'm sure it will fail.
Typically a permit cannot be closed till after a final inspection.
 
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Old 02-01-16, 07:07 PM
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If it is a basic electric OVEN..... like wall oven and not range..... many of those run on straight 240v and don't require a neutral.
 
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Old 02-01-16, 07:11 PM
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It is a oven range.
There are 20 some units being remodeled and all of them have 3 prong. I don't know how they are proceeding with permit.

Maybe they never pulled electrical permit?


--- EDIT ---

Just checked building permit status of this apartment out of curiosity and I found that they only have permit for zoning for increasing load. (increasing number of units).
I never pulled permit in DC before, so I don't know how they work, but doesn't most counties require electrical and plumbing permits as well?
 
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Old 02-02-16, 08:08 AM
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Maybe the kitchen is considered a grandfathered install? Most everywhere would require a permit for a commercial apartment building. Much different than residential.
 
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