Water heater disconnect?

[mtlogcabin]

Would it be code compliant to use a dryer chord on a residential electric water heater? I remember seeing dryer chords used for this purpose in the early 90's in S FL but don't know if it is a correct use.

 

[codeworks]

no. a water heater isn't listed as a cord connected appliance, and the dryer cord isn't listed for use on water heater

 

[globe trekker]

Is the water heater designed / identified for a flexible cord connection?

(RE: Art. 400.7(8), 2008 NEC). Also, I did not see an approved type of

flexible cord (cable assembly) listed in Table 400.4, 2008 NEC for a

water heater.

.

 

[BSSTG]

Greetings,

That's a great way to get someone's fingers fried. Apply 422.11(E)(3). 2011 NEC.

BS

 

[BSSTG]

oooops

It's got to be lockable per 422.31(B)

BS

 

[Dennis]

The easiest way to do this is a dp 30 amp switch in a single gang switch box or use an a/c fuseless disconnect. I usually flex with carflex to the unit from the disco.

I agree water heaters are not to be cord and plug.

 

[Rider Rick]

Greetings,That's a great way to get someone's fingers fried. Apply 422.11(E)(3). 2011 NEC.

BS

BSSTG,

Would the risk to get your fingers fried happen, when you pull the plug out? Asking to better understand.

 

[BSSTG]

BSSTG,Would the risk to get your fingers fried happen, when you pull the plug out? Asking to better understand.

Yessir absolutely,

There is always a possibility of unplugging the unit under load or ground fault conditions. You could have an arcing problem for sure. The Code limits cord and plug disconnect means to lower load appliances, motors, etc. for that reason. You will find restrictions both in Arts 422 for appliances, 430 for motors, others for air conditioners and so forth You have probably seen arcs before when you unplug a pile of Christmas lights or such. You get that bigger arc which can be dangerous the larger the load. It used to be common practice to use appliance cords for disconnects for water heaters here in southeast Tx areas. I've done my best to discourage that practice. Years ago I worked in a dairy plant and we had a lot of cord and plug connected machinery in the production area which was interchangeable. It caused some problems initially when the place was built as the motors on occasion were unplugged under load. A 5 or 10 amp load was serious business when uplugging a cord especially at 480 v. It happened a few times. Scary stuff those electrons!

BSSTG

 

[Gregg Harris]

III. Disconnecting Means

422.30 General. A means shall be provided to simultaneously disconnect each appliance from all ungrounded conductors in accordance with the following sections of Part III. If an appliance is supplied by more than one branch-circuit or feeder, these disconnecting means shall be grouped and identified as the appliance disconnect.

422.31 Disconnection of Permanently Connected Appliances.

(B) Appliances Rated over 300 Volt-Amperes. For permanently connected appliances rated over 300 volt-amperes, the branch-circuit switch or circuit breaker shall be permitted to serve as the disconnecting means where the switch or circuit breaker is within sight from the appliance or is capable of being locked in the open position. The provision for locking or adding a lock to the disconnecting means shall be installed on or at the switch or circuit breaker used as the disconnecting means and shall remain in place with or without the lock installed.

422.16 Flexible Cords.

(A) General. Flexible cord shall be permitted (1) for the connection of appliances to facilitate their frequent interchange or to prevent the transmission of noise or vibration or (2) to facilitate the removal or disconnection of appliances that are fastened in place, where the fastening means and mechanical connections are specifically designed to permit ready removal for maintenance or repair and the appliance is intended or identified for flexible cord connection.