[jiarchibald]

I have a semi finished basement with full bath and a wet bar previously plumed. Both areas share and adjacent wall. I need to add an exhaust fan to the bathroom and I'm planning on adding two 20 amp GFCI plugs on either side of the sink in wet bar and two 20 amp plugs below counter to run a mini fridge and wine fridge. Both rooms and the rest of the basement (lights, outlets, etc.) are on a single 15 amp breaker.

My plan is to run a dual 20/20 tandem circuit from the main panel to the bath and wet bar. leaving the rest of the basement on the 15 amp circuit. the panel is a 200 amp service with room for 3 more breakers. I wanted to save room by using the 20/20 tandem.

My question is, can I do this safely and is this going to bite me in the as* if and when inspections come through.

My understanding of the 20/20 tandem, is that I can run two 20 amp circuits from one breaker. Is this correct?

with this set up if anything trips both the bath and wet bar will go together, is this correct?

 

[k_buz]

You can only install tandems in a panel rated to take tandem breakers.

If you can install tandem breakers, then each "side" of the tandem will work independently of each other.

 

[jiarchibald]

The three open spots can take tandem breakers

 

[theatretch85]

You will have to run separate 12/2 for each circuit from the panel, you cannot use 12/3 to get the two circuits near the bathroom/wetbar area as you would overload the neutral.

 

[eastcoastsparky]

You will have to run separate 12/2 for each circuit from the panel, you cannot use 12/3 to get the two circuits near the bathroom/wetbar area as you would overload the neutral.

He could only run 12/3 if it was a mwbc with a 2 pole breaker

 

[TarheelTerp]

semi finished basement with full bath and a wet bar
Both areas share an adjacent wall.
I need to add an exhaust fan to the bathroom...

Do you already have lighting in that room?

Both rooms and the rest of the basement (lights, outlets, etc.)
are on a single 15 amp breaker.

How many other lights in total?
How many receptacles in total?

 

[jiarchibald]

I will be running 12-2 to both bath an wet bar.

 

[jiarchibald]

How many other lights in total?
How many receptacles in total?

There is one light in bath. Wet bar is open to the rest of the basement so no additional lighting needed.
Not including bath, there will be 12 lights and 10 receptacles on existing 15 amp. 4 lights on single-dimmer and 4 on 3-way w/dimmer. One deck light/ single. And three in stairwell. All three in stair well are on 3-way.

 

[Stubbie]

He could only run 12/3 if it was a mwbc with a 2 pole breaker

I think he was explaining that if the OP was thinking mwbc he could not use a tandem breaker.

 

[Stubbie]

There is one light in bath. Wet bar is open to the rest of the basement so no additional lighting needed.
Not including bath, there will be 12 lights and 10 receptacles on existing 15 amp. 4 lights on single-dimmer and 4 on 3-way w/dimmer. One deck light/ single. And three in stairwell. All three in stair well are on 3-way.

As long as the receptacles in the bathroom are on a 20 amp circuit and gfci protected your good. the receptacle circuit cannot extend out of that single bathroom or hiot any receptacles before the bathroom. Also any receptacles close to a wet bar sink need gfci protection if they serve the countertop. Close meaning this ....


210.8(A)(7) Wet bar sinks
Receptacles installed within 6 feet (1.8 m) of a wet bar sink must be GFCI protected where installed to serve the countertop surfaces. The six foot distance is measured from the outside edge of the sink. Receptacles more than 6 feet (1.8 m) from the sink’s outside edge are not required to be GFCI protected. Receptacles not serving the wet bar’s countertop surface do not require GFCI protection, even if they are within 6 feet (1.8 m) of the sink.

 

[TarheelTerp]

There is one light in bath. Not including bath, there will be 12 lights
and 10 receptacles on the existing 15 amp.

The remedy I'd suggest is to split the existing lights and receptacles.
I suspect that will be easy since the R's were probably added to the lighting circuit.
Keep the 15A for lights (as is) and add the bathroom fan to that.

Provide another (new circuit) for the existing receptacles.
Make it 15 or 20 depending on what wire is used for them.

eta: the original basement plan SHOULD have had at least one 20Amp recep.
Look around for what was provided then and what you have now.
When you're able to sort that out... be sure about the wire used.
---
The remodel work, wet bar outlets and appliances, will need what they need.
Avoid using tandem breakers or MWBC's when you do that.

If you have a shortage of breaker space... fix that.

 

[Stubbie]

The remedy I'd suggest is to split the existing lights and receptacles.

I suspect that will be easy since the R's were probably added to the lighting circuit. Keep the 15A for lights (as is) and add the bathroom fan to that.

Provide another (new circuit) for the existing receptacles.
Make it 15 or 20 depending on what wire is used on them.

Bathroom receptacles must be 20 amp if your talking about the bathroom.

 

[jiarchibald]

I'm trying to run two 20 amp circuits off one 20/20 breaker. mainly because the exhaust in bath and the separate wet bar circuit. I could run just a 20 amp to both fan and wet bar, but with the the rest of the basement on a 15 amp service. I'd like to lighten the load especially with an entertainment section (TV, Music, etc.)

I do have to room for 2 20/amp just thought I'd save space with the tandem

So, I'm guessing I need to return my 20/20 tandem and pick up two 20/amp breakers and run both bath and wet bar on separate breakers.

 

[eastcoastsparky]

I'm not sure what you gents are referring to with MWBC
(main wet bar circuit?) but I'm trying to run two 20 amp circuits off one 20/20 breaker. mainly because the exhaust in bath and the separate wet bar circuit. I could run just a 20 amp to both fan and wet bar, but with the the rest of the basement on a 15 amp service. I'd like to lighten the load especially with an entertainment section (TV, Music, etc.)

Mwbc- multi wire branch circuit. Using a double pole breaker with only one nuetral if one circuit were to trip they both would bc they are handle tied together

 

[Stubbie]

There is nothing wrong with using a tandem breaker to get two 20 amp 120 volt circuits to the bathroom and wet bar. Be sure what you use is indeed a tandem breaker and not a double pole breaker. A tandem will fit in one space with two toggles that are not handle tied. Like so .. cannot use this with mwbc as eastcoastsparky has pointed out. You can also buy them 15/20 instead of both the same

 

[TarheelTerp]

Bathroom receptacles must be 20 amp if your talking about the bathroom.

As I'm reading it... the bathroom is part of the new wet bar work.
But if not... then deal with them when you do the wet bar.

As I'm reading it... the OP will probably need a sub panel for the breaker space all this added on wet bar features (will chew up and is/was hoping to get away with just using tandems).

Whether they meet code or not... I just don't like 'em. Or MWBC's.
I'll repeat: Avoid them both.

 

[k_buz]

As I'm reading it... the bathroom is part of the new wet bar work.
But if not... then deal with them when you do the wet bar.

As I'm reading it... the OP will probably need a sub panel for the breaker space all this added on wet bar features (will chew up and is/was hoping to get away with just using tandems).

Whether they meet code or not... I just don't like 'em. Or MWBC's.
I'll repeat: Avoid them both.

He has three open spaces that all take tandems. He needs two circuits. Why will he need a subpanel?

 

[jiarchibald]

There is nothing wrong with using a tandem breaker to get two 20 amp 120 volt circuits to the bathroom and wet bar. Be sure what you use is indeed a tandem breaker and not a double pole breaker. A tandem will fit in one space with two toggles that are not handle tied. Like so .. cannot use this with mwbc as eastcoastsparky has pointed out. You can also buy them 15/20 instead of both the same

Thanks I am going to use a two pole unit

 

[k_buz]

That is a tandem breaker not a two pole.

 

[jiarchibald]

He has three open spaces that all take tandems. He needs two circuits. Why will he need a subpanel?

I agree