HPWC Installation: Fused or non-fused disconnect switch?

[ctn531]

Installing a HPWC for MX (72A onboard charger). Dedicated 100A breaker in main panel with 2 AWG wire running to my disconnect switch (approx 60 feet). From there, 2 AWG wire running to my HPWC (approx 10 feet).

My question is what situations would warrant a fused disconnect switch compared to a non-fused disconnect switch?

Thanks for the input!

 

[KevinY]

I can't think of any reason to install a fused disconnect if your hpwc is connected to a dedicated circuit breaker.

 

[jboy210]

What is a fused disconnect switch? Is that like the one used for an A/C unit?

 

[ai4px]

I'd go with the nonfused disconnect... it will be fed from a circuit breaker, right?

 

[Rockster]

I can't think of any reason to install a fused disconnect if your hpwc is connected to a dedicated circuit breaker.

I'm not an expert but I believe that something in the electrical code requires a dedicated disconnect if the HPWC is more than a certain distance, or out of sight, from the circuit breaker.

 

[ai4px]

I'm not an expert but I believe that something in the electrical code requires a dedicated disconnect if the HPWC is more than a certain distance, or out of sight, from the circuit breaker.

Found it.... NEC 625.23: EVSE rated more than 60 amp OR more than 150v to ground, disconnecting means shall be provided in a readily acessible location. Must be able to be locked open (off).

240v is NOT >150v to ground, but due to >60amps, you need a disconnect. The code doesn't say a thing about fused disconnect, just that it is lockable in the off position.

 

[SSonnentag]

Code here dictates a disconnect switch must be installed near the load if the load is greater than 50A and the breaker panel is out of sight or on another wall. You don't need a fused disconnect. The breaker will handle that function.

 

[ai4px]

Sonnentag, ich glaube es ist wirklich noch sonnig ins Arizona! Viel spass!

 

[SSonnentag]

Sonnentag, ich glaube es ist wirklich noch sonnig ins Arizona! Viel spass!

Ja, mein Name ist sehr gut für meinen Wohnort.

(Translation courtesy of Google as I don't know German.)

 

[jboy210]

Found it.... NEC 625.23: EVSE rated more than 60 amp OR more than 150v to ground, disconnecting means shall be provided in a readily acessible location. Must be able to be locked open (off).

240v is NOT >150v to ground, but due to >60amps, you need a disconnect. The code doesn't say a thing about fused disconnect, just that it is lockable in the off position.

So does that mean the SSonnentag's breaker box with on/off in the signature picture meets this requirement?

 

[ai4px]

So does that mean the SSonnentag's breaker box with on/off in the signature picture meets this requirement?

Yes, he’s got a cut off switch near the EVSEs.

 

[mongo]

Yes, he’s got a cut off switch near the EVSEs.

The "readily acessible location" is defined as

Accessible, Readily (Readily Accessible). Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles or to resort to portable ladders, and so forth.

So it does not need to be in line of sight of the EVSE if it has a locking means. Also means the breaker at the panel can serve as the disconnecting means with an add on lock out.
Big difference between EVSE and any other >60 Amp load.
(Local requirements may vary)

 

[HugoBoss]

Code is different everywhere. We have a 100amp fuse at panel and a disconnect with a 90amp fuse above charger

 

[eprosenx]

Code here dictates a disconnect switch must be installed near the load if the load is greater than 50A and the breaker panel is out of sight or on another wall. You don't need a fused disconnect. The breaker will handle that function.

Do you have a code reference for this?

This is absolutely not what is written in 2017 NEC.

What is written is that it has to be able to be locked in the off position if greater than 60a amps and it has to be readily accessible.

The definition of “readily accessible” in NEC code says nothing about line of sight or any distance requirements, just it can’t require ladders or tools to get to. Now your local AHJ could interpret this differently.

Also, it is very possible that your local jurisdiction has added their own requirements to the code beyond what is in NEC (hence I am curious about a code reference).

I personally dislike this requirement for local disconnects for EVSE’s as I think they are ugly and expensive and not really needed or relevant. Local disconnects are important for things like HVAC units where you have technicians working on them often and need to turn on/off the power a lot. EVSE’s really have no serviceable parts in them and so it does not seem like much of a burden to find the breaker panel and lock off the breaker in question.

I also don’t get what makes my Wall Connevtor more dangerous once I exceed 60a. It is the same exact unit doing the same thing fed from the same source.

I guess with thicker wiring and a higher amperage breaker there might be slightly more fault current available.

 

[SSonnentag]

Do you have a code reference for this?

This is absolutely not what is written in 2017 NEC.

I followed the direction I received directly from the Yavapai County office in Prescott, Arizona. Codes and regulation vary greatly by county. If I can find the letter I received from the county I'll post it, but I don't get back home for another 8 days.

It probably did say 60A, not 50A as I stated, but I installed 100A anyway, so I didn't pay that close attention.

 

[eprosenx]

I followed the direction I received directly from the Yavapai County office in Prescott, Arizona. Codes and regulation vary greatly by county. If I can find the letter I received from the county I'll post it, but I don't get back home for another 8 days.

It probably did say 60A, not 50A as I stated, but I installed 100A anyway, so I didn't pay that close attention.

Gotcha, yeah, would be curious to see what they said!

If it says 60a then yeah, this is probably a case of different interpretations of "readily accessible". The NEC says nothing about distance or line of sight, however, it leaves a lot that could be interpreted.

 

[davewill]

...
I personally dislike this requirement for local disconnects for EVSE’s as I think they are ugly and expensive and not really needed or relevant. Local disconnects are important for things like HVAC units where you have technicians working on them often and need to turn on/off the power a lot. EVSE’s really have no serviceable parts in them and so it does not seem like much of a burden to find the breaker panel and lock off the breaker in question.
...

It only takes once, and people DO sometimes have to service EVSEs. A lockable breaker is not standard and is sufficient in some inspector's eyes. I know I would want a disconnect. My EVSE is only on a 40a circuit, but uses a plug, and it's comforting to be able to SEE that the power is disconnected when I (admittedly rarely) open it.