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Sir Sparks
Sir Sparks, President/Owner/ Master Electrician
Category: Electrical
Satisfied Customers: 2532
Experience:  US State Certified & UK Electrical Contractor for all electrical fields/disciplines
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I have a main breaker panel in my house w/ a 50 amp breaker

Resolved Question:

I have a main breaker panel in my house w/ a 50 amp breaker which feeds to an outside mounted box which has 2 50amp breakers - 1 feeds an RV, the other feeds my detached garage. Inside the garage there is a panel box which presently has a 20amp double pole breaker as the main breaker. This panel box is shot ( guts falling out of it) and I want to replace it and rewire the garage -the garage will have minimal requirements -(no welders or any high draw equipment). Can I use a "main lug" type box or do I have to use a "main breaker" type box?If I use a main breaker box all I can find so far have at least a 100 amp main breaker -would this be ok? also at some point I intend to convert this garage into a living space ( bunkhouse type -2 bedrooms and a bath - again minimal electrical requirements. If I use a 100amp panel box can I/ should I switch out the main breaker to a 50 amp breaker ??
Submitted: 6 years ago.
Category: Electrical
Expert:  Sir Sparks replied 6 years ago.

Sir Sparks :

Hi.

Sir Sparks :

A moment to read your enquiry please

Sir Sparks :

This is a two part answer.

Sir Sparks :

#1 You may use a main lug only panel as the panel is already protected by a 2 pole breaker.

Sir Sparks :

#2 the maximum size of this breaker will depend on your present wire size feeding this sub-panel and the distance.

JACUSTOMER-g1fippad- :

#1 - I wasn't sure if it was a living space if it had to have a main breaker in the building ?

Sir Sparks :

I think at the time you convert to a living space you will need a second meter anyway and a new service. This will depend on your Supply company and local codes

Sir Sparks :

For now you do not need it.

Sir Sparks :

Also your present arrangement of one 50 feeding two 50's is funky to say the least.

Sir Sparks :

If I were you at present I would do the minimal work needed.

JACUSTOMER-g1fippad- :

is it safe ?? an overload should just trip the breaker in the house ??

Sir Sparks :

Yes it is safe provided all wire sizes are correct and the person that wired this originally obviously didn't know the correct way to do things so I strongly advise checking these wire sizes out.

Sir Sparks :

If you tell me the distances I will tell you minimum wire size and/or max. breaker sizees

JACUSTOMER-g1fippad- :

I am not going to get a second meter/service - this will be a minimally used building for overflow guests

Sir Sparks :

ok

Sir Sparks :

Then when ready I would simply run a new sub-panel feed to the garage

Sir Sparks :

and I would abanddone the present one

Sir Sparks :

abandon

JACUSTOMER-g1fippad- :

distance is 50 feet - wire size is # XXXXX -this wire is alredy to the garage

Sir Sparks :

OK but I need 3 distances here

Sir Sparks :

home to JB, JB to garage, JB to RV

Sir Sparks :

#6 is the correct size for 50 amps max (so far)

Sir Sparks :

#6 COPPER that is.

JACUSTOMER-g1fippad- :

no room in panel box to add any more circuits - home to jb -30ft - jb to garage - 50 ft - jb to rv - 25ft

Sir Sparks :

Understood.

Sir Sparks :

All distances are fine

Sir Sparks :

Do you know the size of wire feeding the JB and RV ?

JACUSTOMER-g1fippad- :

so if building is living space does it need main breaker in building or will main lug box be acceptable ? It is all #6 wire

Sir Sparks :

In this situation it needs a main breaker, however this breaker does not need to match the size of the feed breaker as it will simply be used as a Fire DEPARTMENT DISCONNECT.

Sir Sparks :

Your max breaker sizes are as you already have.

Sir Sparks :

You may installa 100 amp in your new panel as you will still only obtain 50 amps max

Sir Sparks :

However there is a simpl way to fit a 50 amp too.

Sir Sparks :

That is a 50 amp feed breaker to a main lug panel

JACUSTOMER-g1fippad- :

ok - i will go with whichever I can find easiest and cheapest - 100 amp panels are easy to come by and fairly cheap

Sir Sparks :

OK I agree.

JACUSTOMER-g1fippad- :

and it will serve my purpose - thank you - really wasn't sure if I needed the main breaker in a living space but it makes sense

Sir Sparks :

If not just ask for a "retention kit" cost a few dollars and you can use any size breaker you choose to fit at the top of the buss for a main disconnect. 50 amp being preferable here so as not to confuse people.

Sir Sparks :

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JACUSTOMER-g1fippad- :

that is true - I will do that if I can find it easy enough - not easy to find good help at home depot

Sir Sparks :

Yes it is actually I'll explain;

Sir Sparks :

Call Home Depot and ask when their Master Electrician is on duty, nearly every HD has one

Sir Sparks :

If they don't simply try another HD

Sir Sparks :

if you don't get to him don't accept anyone eslses advice I have heard of some crazy things being told there

JACUSTOMER-g1fippad- :

ok - i will try that - I know one that has a master plumber - he has been very helpful - never found any one competent in the electrical dept yet though

Sir Sparks :

make a few calls

JACUSTOMER-g1fippad- :

thanks again

Sir Sparks :

Thank you. Good luck. When it does come time to upgrade the garage to 100 amps please ask my advice first.

Sir Sparks :

Perhaps even install the inexpensive 2" PVC conduit this summer when it is warm

Sir Sparks :

Just go straight from present main panel location to garage

Sir Sparks :

Use no more than 2 90 degree bens if possible.

JACUSTOMER-g1fippad- :

I really don't think I need that much in that building - and as I said - no room in the main panel box

Sir Sparks :

4 90's is the MAX but that would be a bear to pull the wires after

Sir Sparks :

Well remember you don't really have 50 amps

Sir Sparks :

you have 50 less what the RV is using

Sir Sparks :

You could easily add a sub-panel to the side of the main panel too.

Sir Sparks :

Total material costs about $50

JACUSTOMER-g1fippad- :

I just need a couple light circuits and outlet cicuits - there will be minimal use of this building -

Sir Sparks :

THEN YOU ARE FINE.

Sir Sparks :

I was just trying to prevent you wasting money

JACUSTOMER-g1fippad- :

ok - thanks

Sir Sparks :

Thaank you

Sir Sparks :

Please remember to click the "accept" button

Sir Sparks :

Now should work.

Sir Sparks :

OOPs

Sir Sparks :

I mean NOW (I had it locked out)

Sir Sparks and other Electrical Specialists are ready to help you

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