30A-120V SERVICE: (US/CAN)

 Most RV’s have a 30A service outlet to power internal appliances and RV outlets.
This is done using the RV 30A power cable connected to the camping TT-30R power outlet.

The cable is the standard RV TT-30P (plug) to an L5-30R twistlock.

THIS IS A 3 BLADES 30A- 120V SERVICE,  THIS IS NOT 240V,
Make sure you explain to your electrician. Even campgrounds have made this mistake !

Typically this will power:
--Microwave,
--120v Power outlets,
--120v GFI External, and lavatory outlet,   
--12v-Battery charger,
-- the fridge when in Electrical mode,
-- Water heater in Elec mode,
-- and Air Conditioning unit (only with 30A service)

  

 
TYPICAL RV PARK PEDESTAL 

 US/CAN & UK DIST.

 US/CAN are -split-line-   120V distribution ( LINE-NEUTRAL-LINE)
providing  120V  from either   LINE and NEUTRAL, and  240V across the two LINES.(L1 & L2)

UK & most of  Europe residential dist. is single phase  230V  (LINE- NEUTRAL)

See  the  basics here: 

Typical UK Dist:

TYPICAL 30A RV HOOK-UP

TYPICAL RV PARK PEDESTAL WIRING (US/CAN) 

US-CAN Residential Breaker panel topology 

TT-30-R 

 50A – 120V/240V SERVICE: (US/CAN)

 Larger RV’s have a 50A service outlet to power both; 120v and 240v internal appliances and outlets.

This is done using the RV 50A power cable connected to the camping 14-50R 240V power outlet (same as residential ).

The cable is the standard 14-50P (plug) to an SS2-50R twistlock. Typically this will power:
--Microwave,
--120v Power outlets,
--120v GFI Ext. and lavatory outlet,
-- 12v-Battery charger,
--the fridge when in Electrical mode,
--Water heater in Elec mode ,
-- 2 Air Conditioning units,
--and 240v appliances (dryer)

 TYPICAL 50A  RV HOOKUP 

 Understanding  50A  hookup:

 50A RV CABLE

TWISTLOCK FIRE HAZARD

 50% of  RV  fires  are  ELECTRICAL  ! mostly due  to twistlock damaged contacts from moisture, bad contact which create an overheat condition. A bad contact increse resistance and temperature.  Improper   lock by  not correctly turning the plug will  result in partial contact and lose contact.  ALL  this may happen  BEFORE  the breaker trips  as  a lower current is all it  needs to produce this condition.

 But a solution for this :replace your  twistlock with   --SmartPLug !--
Safe, water proof, more contact surface, direct insert and lock , no twist required and  designed for  Naval and RV  application.

www.smartplug.com

 BURNED TWIST LOCK

 POWER SURGE PROTECTION & FILTERING

 If you invest on a  50-- 100K$ RV , you need AC power surge protection ! this is a must !

A surge protector might seem expensive, but it’s an absolutely essential RV electrical safety accessory. Not only will a surge protector protect your RV electrical system from being fried by a faulty pedestal, but it can also save your life!

Also many RV parks are affected by total RV’s loads resulting in grid unstable voltage and voltage drop down to 90V !

Intelligent Electrical Managing System will protect your appliances and electronics:
With an automatic shut-OFF feature , they will: trip for under/over voltages, surges, lightning strikes, high level AC noise, and incorrect wiring.

Typical Watch DOG Smart RV surge Protector:

TYPICAL EMS 

TYPICAL EMS 

 POWER ADAPTORS- DOGBONE

 To plug  your RV into a  different plug rating than the  one  fitted  for  your RV, 
you  may need to  use  a  power adaptor.
There are plenty of adaptors out there that convert a 50A plug into a 30A plug
for your RV, or  vice-versa. 

These devices are commonly known as -dogbone- adaptors and are relatively cheap.
However, it’s important to understand that there are risks associated with these adaptors. 
The dogbone adaptors above are commonly referred to as “dumb” adaptors.
The    term “dumb” refers to the fact that these adaptors do not  contain any inteligence and
do not offer protection for your RV and can lead to a possible overload on your RV’s cable.

-----  30A RV TO A  50A SERVICE   :

The most  popular question on  adaptors:
----Can You Hook Up a 30 Amp RV to a 50 Amp Power Plug?---

YES !  but : 

it’s not as simple as just plugging in your RV and hoping for the best. You really need to understand what you are doing and take appropriate safety measures to mitigate the risk of damage to your electrical system and  yourself. 

When you plug a 30 amp adapter into a 50 amp 14-50R plug at the pedestal, the 50 amp breaker will only trip if the current goes above 50 amps. The problem here is that these adaptors and the power cord for your RV are only rated for 30A . This means you have an unprotected line section  with the potential to be overloaded by 20 amps, which is not safe !!.

But  since  the RV’s main breaker installed in the distribution panel is probably rated for  30A, the above scenario is unlikely. Most of the time, the RV’s main breaker will trip before the 50A pedestal breaker does. Not to mention, even with the RV’s breaker, using a 50A/30A dogbone adapter without protection is technically an electrical code violation.

LIMITATIONS:

Take note by  using the   above  adaptor still limit your maximum current to 30A, 
(3600W) not 50A (12KW) ,  you  are  infact using 1 x 120V leg of the 240V outlet.
Larger RV's equiped with 50A  service are  using 2x 120V legs (L1 & L2, 240V)

 ---- 50A RV TO A  30A SERVICE:

This time, however, the simple dogbone adaptors work safely. This is because too much amperage will trip the 30A pedestal  breaker, keeping it from overloading the line. This simple, inexpensive adapter will do the trick:

LIMITATIONS:
This does limit your  power to 30A, (not 50A).
and 240V  appliances wont work, since you are  feeding only 1x 120V leg of  your distribution.

50A to 30A ADAPTOR

 Typical  14-50P to  TT-30R 

Unsafe line  section  shown: 

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 LINE PROTECTION:

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30A TO 50A ADAPTOR 

Typical TT-30P to 14-50R 

This is the content for Layout P Tag

120V 5-15P TO TT-30R ADAPTOR 

BONDING-NEUTRAL

 Why NEUTRAL and Ground are   bonded  ONLY  at  one place ?
The MAIN panel. NOT IN YOUR  RV !

ANS:

Most appliance  have a  3rd  pin called  ground  to provide Electrical  safety.  When a  fault  occur (live voltage   touching the casing)  the  flow will  increase rapidely through a  return path and trip  a  breaker.   But  since the real  retrun path is  back  to the  source: ei: the NEUTRAL, at the end  point the  grounding  system needs to be  connected to the NEUTRAL .

See an explanation with  Benjamin Sahlstrom: Neutral- Ground.

Why on  Sub Panel or in  your RV  you  DONT bond NEUTRAL to Ground ?

ANS:  you  cannot  have residual  current traveling  on  both path : NEUTRAL and  ground .  Current will  split  and travel on  the NEUTRAL  conductor, but  also on  the Ground conductor.  A ground system should be a NON-Carying conductor.

when we bond them together, it gives your neutral wire (the one carrying electrical currents BACK to the source) multiple pathways. That’s how the chassis of some equipment will become energized. The effect can be as seemingly harmless as “I touched the fridge, and it shocked me!” To far more serious matters. 


See an explanation with  Benjamin Sahlstrom: Why NEUTRAL not bonded to Ground on  Sub-panel.   

       

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