4C Mount Mailboxes FAQ

How many types of 4C mailboxes do you carry?

We carry 3 main types of 4C mailboxes including:

Pedestal Mount 4C Mailboxes – designed for use outdoors where mailboxes are installed on a pedestal stand.

Front Loading Surface Mount 4C Mailboxes – designed for indoor use and installed onto the wall surface.

Rear Loading Recessed 4C Mailboxes – designed for indoor use and installed into an opening within a wall with rear access from a private locked room.

Do 4C mailboxes need USPS approval?

Yes. All centralized mail delivery mailboxes serviced by the USPS must be USPS approved before installation.

Are there height restrictions for pedestal 4C mailbox installation?

Yes. Only the USPS can specify the exact height requirements.

Do you provide installation Instructions for 4C pedestal mailboxes?

Yes, the MailboxWorks does provide 4C Pedestal Installation Instructions.

What if I don’t need an outgoing mail slot?

USPS prohibits the removal or modification of outgoing mail slots.

Can I buy additional tenant keys?

Yes, you can order additional tenant door keys from The MailboxWorks here.

What if I don’t need a parcel locker?

USPS requires that all commercial 4C pedestal mailboxes have a parcel locker if there are 10 mailboxes or more. The parcel lockers may not be altered in any way.

Does the MailboxWorks carry 4C mailbox replacement parts?

Yes, the MailboxWorks also carries 4C mailbox replacement doors, hinges, and rods/pins. Call us at (866) 717-4943 to order.

Can I customize my tenant mailbox doors?

Yes, the USPS does allow you to add custom door decals or engraved characters (up to 12 characters per line – 2 lines maximum).

Who do I contact regarding the placement location of a new or replacement 4C mailbox?

Contact your local postmaster to determine where to install your new mailbox. They can also provide you with details on what mailbox unit is needed for replacement. Do not contact your local letter carrier.

What is the difference between a recessed 4C mailbox and a surface mount 4C mailbox?

Recessed mount mailboxes are installed into a rough opening in a wall that is made to fit the exact length, width, and depth of the mailbox unit. Surface mount mailboxes are installed on a flat surface.

Are there USPS regulations about wall or pedestal mount mailboxes?

Please contact your local postmaster to review your specific mailbox installation location needs in order to determine the right option for your application.

I have noticed that these mailbox units have a longer ship time than CBU mailboxes. Why is that?

4C mailbox units are custom made to order, which requires additional lead time at the manufacturer’s level. CBU mailboxes are pre-made and ready to ship to the buyer as soon as the order is placed.

How big is the outgoing mail slot on these mailbox units?

The outgoing mail slot is 3/4″H x 12″W.

Does the outgoing mail slot on the 4C mailbox unit offer theft protection?

Yes. There is an aluminum comb on the outgoing mail slot that helps prevent mail fishing and the removal of outgoing mail.

Can I remove the outgoing mail slot?

No. The mail slot and compartment cannot be removed.

Can a USPS 4C mailbox be customized with a private mail slot?

No. Only the USPS can place items in 4C mailboxes that are serviced by the USPS. Adding your own private mail slots can compromise the security of the mailbox unit and enable mail fishing.

I just received my new 4C mailbox unit but cannot find the keys. Where are they?

Keys for 4C mailboxes with parcel lockers can be found in the left side parcel locker along with the hardware and installation instructions. To open the parcel lockers, reach into the center of the unit and push on the bracket located in the upper left corner. This will open the right-side gate and allow you to open the left-side gate, give you access to the left side parcel compartment.

Keys for 4C mailboxes without parcel lockers can be found in one of the tenant door compartments along with the hardware and installation instructions.

Note: Before completing the following steps, please make sure your 4C unit is securely placed on a flat surface so it does not fall over when the master front door is open.

How do I get a master door lock for my 4C mailbox?

Once you have installed the mailbox unit, contact your local post office to come and install the master lock(s) on your new 4C mailbox(es). This can only be done by the USPS.

How many characters can be engraved on the mailbox doors?

You can engrave up to 12 characters per line and up to two lines.

What size of numbers can be engraved on the mailbox?

All engraved characters are 3/4″ tall.

What size of decals are used for mailbox door indentification?

All mailbox door decals are 1.5″ x 1.75″.

How many characters fit on a decal?

Up to five characters fit on a decal.

What is a parcel locker?

Parcel lockers are the part of a 4C mailbox used for package delivery to store oversized packages that do not fit into the individual tenant’s mailbox.

How does package delivery to a parcel locker work?

Sometimes a tenant will receive a package that does not fit into their individual tenant mailbox. The USPS mail carrier will put a key tag and instructions in the tenant’s mail slot and secure the package in one of the parcel lockers. The key tag and instructions give the tenant/recipient access to the larger parcel locker. All the tenant needs to do is open the corresponding parcel locker with the provided key and remove their package. Once the key is inserted into the parcel locker lock, it cannot be removed until it is retrieved by the mail carrier.

What is a captive lock?

4C mailboxes have a captive lock on all parcel lockers, which means once the key is inserted, it can only be removed by the authorized mail carrier.

Can I use the parcel locker as an extra tenant mailbox?

No. Parcel lockers have a captive lock and do not work the same as tenant mailboxes. Furthermore, the USPS regulations restricts 4C parcel lockers from being removed, changed, or modified for any other purposes other than parcel delivery by the USPS.

Does the USPS require parcel lockers?

Yes. All locations with ten or more mailbox compartments require a parcel locker. At their discretion, your postmaster may approve a 4C mailbox with no parcel locker in the case that an alternate secure receiving facility is available.

Do all 4C mailboxes come with parcel lockers?

No. There are also 4C mailboxes without parcel lockers for units with less than ten tenant doors. Larger 4C mailboxes without parcel lockers are available for locations that have a USPS approved alternate secure receiving facility.

What does “centralized mail delivery” mean?

It is a form of mail delivery where a local mail carrier delivers and collects mail at one central mailbox unit rather than to each individual residence.

What are the benefits of a centralized mail delivery system to 4C mailbox units?

Whether it is a single-family subdivision or multifamily or office complex, 4C centralized mail delivery improves mail delivery services. Mail is delivered to a convenient central location. USPS mail carriers are able to make multiple deliveries with just one stop, which results in faster service, lower fuel consumption, and lower carbon emissions.

Can 4C mailboxes be used as a centralized mail delivery system?

4C mailboxes are “clustered” style community mailboxes designed for centralized mail delivery. This includes CBU mailboxes (or cluster box units), which are free-standing and mounted on a pedestal, plus other types of STD-4C compliant cluster mailboxes that are mounted on (or in) a wall, a kiosk, or an outdoor mailbox shelter.

Do I need a STD-4C compliant mailbox system?

Yes. As of October 5, 2006, all new construction and major renovation projects require the new “4C” postal standard mailbox units that are U.S. Postal Service compliant.

What makes the new STD-4C compliant mailbox system different?

The USPS changed several factors with the new STD-4C compliant mailbox system:
– Mailbox Shape: The traditional cube style mailbox compartments have been updated to a flatter style horizontal compartments. The new minimum size requirement is 12″W x 15″D x 3″H.
– Mailbox Shape: The new 4C mailbox units incorporate a fully integrated (or stand-alone) parcel locker option. A minimum of one parcel locker per ten tenant mailbox compartments is required.
– Mailbox Security: They also have strengthened security requirements for the entire mailbox receptacle and an improved standardized tenant mailbox compartment lock design.
– ADA Compliant: New STD-4C mailbox systems also meet the requirements of the Americans with Disabilities Act (ADA).

Please explain what the USPS-STD-4B+ Standard means.

The USPS developed the STD4B+ standard in an effort to improve mailbox security. They did this by strengthening and improving the arrow lock compartment of the mailbox master door. This standard is applied to vertical commercial mailboxes as well as apartment complex mailboxes.

Can I install standard USPS-STD-4B+ mailboxes?

As of October 2006, 4B+ vertical and 4B+ horizontal mailboxes are only approved for replacement and/or retrofit installations. New construction and major remodels require that Florence Versatile 4C horizontal mailboxes be installed.

How do the new regulations affect what type of centralized mailbox I buy?

Ask yourself these three questions to determine what type of community mailbox system the USPS requires for your project:
1. Is the mailbox being used for new construction?
If it is, only 4C rated mailboxes or free-standing CBU mailboxes can be used.
2. If it is a renovation, will the new mailboxes be used as replacements in the same rough opening (RO)?
If you say yes, then 4B+ rated vertical or horizontal mailboxes can be used.
3. Is the community mailbox installation inside or outside?
If it is inside, any community mailbox model can be used depending on your answer to the above questions. If it is installed outside, install 4C mailboxes, as the 4B+ mailboxes are not rated for outside use.

How were the USPS standards set?

The USPS first studied various factors like mail size, the volume of mail received, the mail delivery system efficiency, and other things such as mail theft and vandalism. These factors, along with forecasting the future needs of efficient mail delivery, helped the USPS to create an Apartment Consensus Committee. The committee reviewed the findings in order to make more informed decisions about community mailboxes. This committee included representation from mailbox manufacturers like Auth Florence Manufacturing, plus mailbox service providers, resellers, property management companies, and owners, as well as members of the USPS. Following a year of meetings and discussions, the committee agreed on a set of new mailbox requirements. These STD-4C regulations are now mandatory for centralized mail delivery systems serviced by the USPS.

What is the purpose of the new 4C standards?

Ultimately, the regulations are designed to improve mail service.

Will mailbox regulations change again soon?

Prior to the October 2006 change in regulation, the USPS last revised mailbox standards in 1975. These previous standards were used for 30 years and were effective for the drastic increases in mail delivery during that period. It is not easy or quick to change mailbox standards. The USPS aims to ensure these new mailbox standards will protect and manage future mail trends.

How can I tell if a mailbox meets USPS requirement?

4C mailbox manufacturer Florence Manufacturing, places a USPS Approved Logo on each mailbox product that meets these STD-4C mailbox requirements. At MailboxWorks, we offer an extensive range of USPS approved community mailbox products. Our customers can shop the versatile 4C mailbox suite collection to mix and match 4C modules for the perfect configuration. Prior to starting, we encourage you to check with your local postmaster about mailbox requirements and any changes to your building’s mail delivery system.

Where is the manufacturer’s name on the mailbox?

You can find the manufacturer name on the front of the mailbox unit, typically on the Outgoing Mail door or in one of the bottom corners.